diff --git a/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDescriptorFactory.cs b/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDescriptorFactory.cs
index c3504800a5..aae43d1ab8 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDescriptorFactory.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDescriptorFactory.cs
@@ -15,7 +15,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
     /// <summary>
     /// Factory for <see cref="TagHelperDescriptor"/>s from <see cref="ITypeInfo"/>s.
     /// </summary>
-    public static class TagHelperDescriptorFactory
+    public class TagHelperDescriptorFactory
     {
         private const string DataDashPrefix = "data-";
         private const string TagHelperNameEnding = "TagHelper";
@@ -33,29 +33,49 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 
         private static readonly ITypeInfo StringTypeInfo = new RuntimeTypeInfo(typeof(string).GetTypeInfo());
 
+#if !DOTNET5_4
+        private readonly TagHelperDesignTimeDescriptorFactory _designTimeDescriptorFactory;
+#endif
+        private readonly bool _designTime;
+
         // TODO: Investigate if we should cache TagHelperDescriptors for types:
         // https://github.com/aspnet/Razor/issues/165
 
         public static ICollection<char> InvalidNonWhitespaceNameCharacters { get; } = new HashSet<char>(
             new[] { '@', '!', '<', '/', '?', '[', '>', ']', '=', '"', '\'', '*' });
 
+        /// <summary>
+        /// Instantiates a new <see cref="TagHelperDescriptorFactory"/>.
+        /// </summary>
+        /// <param name="designTime">
+        /// Indicates if <see cref="TagHelperDescriptor"/>s should be created for design time.
+        /// </param>
+        public TagHelperDescriptorFactory(bool designTime)
+        {
+#if !DOTNET5_4
+            if (designTime)
+            {
+                _designTimeDescriptorFactory = new TagHelperDesignTimeDescriptorFactory();
+            }
+#endif
+
+            _designTime = designTime;
+        }
+
         /// <summary>
         /// Creates a <see cref="TagHelperDescriptor"/> from the given <paramref name="typeInfo"/>.
         /// </summary>
         /// <param name="assemblyName">The assembly name that contains <paramref name="type"/>.</param>
         /// <param name="typeInfo">The <see cref="ITypeInfo"/> to create a <see cref="TagHelperDescriptor"/> from.
         /// </param>
-        /// <param name="designTime">Indicates if the returned <see cref="TagHelperDescriptor"/>s should include
-        /// design time specific information.</param>
         /// <param name="errorSink">The <see cref="ErrorSink"/> used to collect <see cref="RazorError"/>s encountered
         /// when creating <see cref="TagHelperDescriptor"/>s for the given <paramref name="typeInfo"/>.</param>
         /// <returns>
         /// A collection of <see cref="TagHelperDescriptor"/>s that describe the given <paramref name="typeInfo"/>.
         /// </returns>
-        public static IEnumerable<TagHelperDescriptor> CreateDescriptors(
+        public virtual IEnumerable<TagHelperDescriptor> CreateDescriptors(
             string assemblyName,
             ITypeInfo typeInfo,
-            bool designTime,
             ErrorSink errorSink)
         {
             if (typeInfo == null)
@@ -68,12 +88,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 throw new ArgumentNullException(nameof(errorSink));
             }
 
-            if (ShouldSkipDescriptorCreation(designTime, typeInfo))
+            if (ShouldSkipDescriptorCreation(typeInfo))
             {
                 return Enumerable.Empty<TagHelperDescriptor>();
             }
 
-            var attributeDescriptors = GetAttributeDescriptors(typeInfo, designTime, errorSink);
+            var attributeDescriptors = GetAttributeDescriptors(typeInfo, errorSink);
             var targetElementAttributes = GetValidHtmlTargetElementAttributes(typeInfo, errorSink);
             var allowedChildren = GetAllowedChildren(typeInfo, errorSink);
 
@@ -83,8 +103,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                     assemblyName,
                     attributeDescriptors,
                     targetElementAttributes,
-                    allowedChildren,
-                    designTime);
+                    allowedChildren);
 
             return tagHelperDescriptors.Distinct(TagHelperDescriptorComparer.Default);
         }
@@ -99,24 +118,23 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 attribute => ValidHtmlTargetElementAttributeNames(attribute, errorSink));
         }
 
-        private static IEnumerable<TagHelperDescriptor> BuildTagHelperDescriptors(
+        private IEnumerable<TagHelperDescriptor> BuildTagHelperDescriptors(
             ITypeInfo typeInfo,
             string assemblyName,
             IEnumerable<TagHelperAttributeDescriptor> attributeDescriptors,
             IEnumerable<HtmlTargetElementAttribute> targetElementAttributes,
-            IEnumerable<string> allowedChildren,
-            bool designTime)
+            IEnumerable<string> allowedChildren)
         {
             TagHelperDesignTimeDescriptor typeDesignTimeDescriptor = null;
 
 #if !DOTNET5_4
-            if (designTime)
+            if (_designTime)
             {
                 var runtimeTypeInfo = typeInfo as RuntimeTypeInfo;
                 if (runtimeTypeInfo != null)
                 {
                     typeDesignTimeDescriptor =
-                        TagHelperDesignTimeDescriptorFactory.CreateDescriptor(runtimeTypeInfo.TypeInfo.AsType());
+                        _designTimeDescriptorFactory.CreateDescriptor(runtimeTypeInfo.TypeInfo.AsType());
                 }
             }
 #endif
@@ -387,10 +405,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             return validName;
         }
 
-        private static IEnumerable<TagHelperAttributeDescriptor> GetAttributeDescriptors(
-            ITypeInfo type,
-            bool designTime,
-            ErrorSink errorSink)
+        private IEnumerable<TagHelperAttributeDescriptor> GetAttributeDescriptors(ITypeInfo type, ErrorSink errorSink)
         {
             var attributeDescriptors = new List<TagHelperAttributeDescriptor>();
 
@@ -400,7 +415,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             var accessibleProperties = type.Properties.Where(IsAccessibleProperty);
             foreach (var property in accessibleProperties)
             {
-                if (ShouldSkipDescriptorCreation(designTime, property))
+                if (ShouldSkipDescriptorCreation(property))
                 {
                     continue;
                 }
@@ -415,7 +430,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 TagHelperAttributeDescriptor mainDescriptor = null;
                 if (property.HasPublicSetter)
                 {
-                    mainDescriptor = ToAttributeDescriptor(property, attributeName, designTime);
+                    mainDescriptor = ToAttributeDescriptor(property, attributeName);
                     if (!ValidateTagHelperAttributeDescriptor(mainDescriptor, type, errorSink))
                     {
                         // HtmlAttributeNameAttribute.Name is invalid. Ignore this property completely.
@@ -443,7 +458,6 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                     parentType: type,
                     errorSink: errorSink,
                     defaultPrefix: attributeName + "-",
-                    designTime: designTime,
                     isInvalid: out isInvalid);
                 if (indexerDescriptor != null &&
                     !ValidateTagHelperAttributeDescriptor(indexerDescriptor, type, errorSink))
@@ -509,9 +523,9 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 nameOrPrefix);
         }
 
-        private static bool ShouldSkipDescriptorCreation(bool designTime, IMemberInfo memberInfo)
+        private bool ShouldSkipDescriptorCreation(IMemberInfo memberInfo)
         {
-            if (designTime)
+            if (_designTime)
             {
                 var editorBrowsableAttribute = memberInfo
                     .GetCustomAttributes<EditorBrowsableAttribute>()
@@ -594,27 +608,22 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             return isValid;
         }
 
-        private static TagHelperAttributeDescriptor ToAttributeDescriptor(
-            IPropertyInfo property,
-            string attributeName,
-            bool designTime)
+        private TagHelperAttributeDescriptor ToAttributeDescriptor(IPropertyInfo property, string attributeName)
         {
             return ToAttributeDescriptor(
                 property,
                 attributeName,
                 property.PropertyType.FullName,
                 isIndexer: false,
-                isStringProperty: StringTypeInfo.Equals(property.PropertyType),
-                designTime: designTime);
+                isStringProperty: StringTypeInfo.Equals(property.PropertyType));
         }
 
-        private static TagHelperAttributeDescriptor ToIndexerAttributeDescriptor(
+        private TagHelperAttributeDescriptor ToIndexerAttributeDescriptor(
             IPropertyInfo property,
             HtmlAttributeNameAttribute attributeNameAttribute,
             ITypeInfo parentType,
             ErrorSink errorSink,
             string defaultPrefix,
-            bool designTime,
             out bool isInvalid)
         {
             isInvalid = false;
@@ -689,28 +698,26 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 attributeName: prefix,
                 typeName: dictionaryTypeArguments[1].FullName,
                 isIndexer: true,
-                isStringProperty: StringTypeInfo.Equals(dictionaryTypeArguments[1]),
-                designTime: designTime);
+                isStringProperty: StringTypeInfo.Equals(dictionaryTypeArguments[1]));
         }
 
-        private static TagHelperAttributeDescriptor ToAttributeDescriptor(
+        private TagHelperAttributeDescriptor ToAttributeDescriptor(
             IPropertyInfo property,
             string attributeName,
             string typeName,
             bool isIndexer,
-            bool isStringProperty,
-            bool designTime)
+            bool isStringProperty)
         {
             TagHelperAttributeDesignTimeDescriptor propertyDesignTimeDescriptor = null;
 
 #if !DOTNET5_4
-            if (designTime)
+            if (_designTime)
             {
                 var runtimeProperty = property as RuntimePropertyInfo;
                 if (runtimeProperty != null)
                 {
                     propertyDesignTimeDescriptor =
-                        TagHelperDesignTimeDescriptorFactory.CreateAttributeDescriptor(runtimeProperty.Property);
+                        _designTimeDescriptorFactory.CreateAttributeDescriptor(runtimeProperty.Property);
                 }
             }
 #endif
diff --git a/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDescriptorResolver.cs b/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDescriptorResolver.cs
index d96346ea0a..895d2e12cd 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDescriptorResolver.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDescriptorResolver.cs
@@ -24,7 +24,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             };
 
         private readonly TagHelperTypeResolver _typeResolver;
-        private readonly bool _designTime;
+        private readonly TagHelperDescriptorFactory _descriptorFactory;
 
         /// <summary>
         /// Instantiates a new instance of the <see cref="TagHelperDescriptorResolver"/> class.
@@ -32,7 +32,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <param name="designTime">Indicates whether resolved <see cref="TagHelperDescriptor"/>s should include
         /// design time specific information.</param>
         public TagHelperDescriptorResolver(bool designTime)
-            : this(new TagHelperTypeResolver(), designTime)
+            : this(new TagHelperTypeResolver(), new TagHelperDescriptorFactory(designTime))
         {
         }
 
@@ -41,12 +41,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// specified <paramref name="typeResolver"/>.
         /// </summary>
         /// <param name="typeResolver">The <see cref="TagHelperTypeResolver"/>.</param>
-        /// <param name="designTime">Indicates whether resolved <see cref="TagHelperDescriptor"/>s should include
-        /// design time specific information.</param>
-        public TagHelperDescriptorResolver(TagHelperTypeResolver typeResolver, bool designTime)
+        /// <param name="descriptorFactory">The <see cref="TagHelperDescriptorFactory"/>.</param>
+        public TagHelperDescriptorResolver(
+            TagHelperTypeResolver typeResolver,
+            TagHelperDescriptorFactory descriptorFactory)
         {
             _typeResolver = typeResolver;
-            _designTime = designTime;
+            _descriptorFactory = descriptorFactory;
         }
 
         /// <inheritdoc />
@@ -137,7 +138,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 
             // Convert types to TagHelperDescriptors
             var descriptors = tagHelperTypes.SelectMany(
-                type => TagHelperDescriptorFactory.CreateDescriptors(assemblyName, type, _designTime, errorSink));
+                type => _descriptorFactory.CreateDescriptors(assemblyName, type, errorSink));
 
             return descriptors;
         }
diff --git a/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactory.cs b/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactory.cs
index 22757e37a2..2912b79886 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactory.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactory.cs
@@ -3,6 +3,7 @@
 
 #if !DOTNET5_4 // Cannot accurately resolve the location of the documentation XML file in coreclr.
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
@@ -10,6 +11,7 @@ using System.Linq;
 using System.Reflection;
 using Microsoft.AspNet.Razor.Compilation.TagHelpers;
 using Microsoft.AspNet.Razor.TagHelpers;
+using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -17,8 +19,11 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
     /// Factory for providing <see cref="TagHelperDesignTimeDescriptor"/>s from <see cref="Type"/>s and
     /// <see cref="TagHelperAttributeDesignTimeDescriptor"/>s from <see cref="PropertyInfo"/>s.
     /// </summary>
-    public static class TagHelperDesignTimeDescriptorFactory
+    public class TagHelperDesignTimeDescriptorFactory
     {
+        private readonly ConcurrentDictionary<int, XmlDocumentationProvider> _documentationProviderCache =
+            new ConcurrentDictionary<int, XmlDocumentationProvider>();
+
         /// <summary>
         /// Creates a <see cref="TagHelperDesignTimeDescriptor"/> from the given <paramref name="type"/>.
         /// </summary>
@@ -27,7 +32,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// </param>
         /// <returns>A <see cref="TagHelperDesignTimeDescriptor"/> that describes design time specific information
         /// for the given <paramref name="type"/>.</returns>
-        public static TagHelperDesignTimeDescriptor CreateDescriptor(Type type)
+        public TagHelperDesignTimeDescriptor CreateDescriptor(Type type)
         {
             if (type == null)
             {
@@ -66,8 +71,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// </param>
         /// <returns>A <see cref="TagHelperAttributeDesignTimeDescriptor"/> that describes design time specific
         /// information for the given <paramref name="propertyInfo"/>.</returns>
-        public static TagHelperAttributeDesignTimeDescriptor CreateAttributeDescriptor(
-            PropertyInfo propertyInfo)
+        public TagHelperAttributeDesignTimeDescriptor CreateAttributeDescriptor(PropertyInfo propertyInfo)
         {
             if (propertyInfo == null)
             {
@@ -77,7 +81,6 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             var id = XmlDocumentationProvider.GetId(propertyInfo);
             var declaringAssembly = propertyInfo.DeclaringType.Assembly;
             var documentationDescriptor = CreateDocumentationDescriptor(declaringAssembly, id);
-
             if (documentationDescriptor != null)
             {
                 return new TagHelperAttributeDesignTimeDescriptor
@@ -90,31 +93,51 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             return null;
         }
 
-        private static DocumentationDescriptor CreateDocumentationDescriptor(Assembly assembly, string id)
+        private XmlDocumentationProvider GetXmlDocumentationProvider(Assembly assembly)
         {
-            var assemblyLocation = assembly.Location;
+            var hashCodeCombiner = HashCodeCombiner.Start();
+            hashCodeCombiner.Add(assembly);
+            hashCodeCombiner.Add(CultureInfo.CurrentCulture);
+            var cacheKey = hashCodeCombiner.CombinedHash;
 
-            if (string.IsNullOrEmpty(assemblyLocation) && !string.IsNullOrEmpty(assembly.CodeBase))
+            var documentationProvider = _documentationProviderCache.GetOrAdd(cacheKey, valueFactory: _ =>
             {
-                var uri = new UriBuilder(assembly.CodeBase);
+                var assemblyLocation = assembly.Location;
 
-                // Normalize the path to a UNC path. This will remove things like file:// from start of the uri.Path.
-                assemblyLocation = Uri.UnescapeDataString(uri.Path);
-            }
+                if (string.IsNullOrEmpty(assemblyLocation) && !string.IsNullOrEmpty(assembly.CodeBase))
+                {
+                    var uri = new UriBuilder(assembly.CodeBase);
+
+                    // Normalize the path to UNC path. This will remove things like file:// from start of uri.Path.
+                    assemblyLocation = Uri.UnescapeDataString(uri.Path);
+                }
+
+                // Couldn't resolve a valid assemblyLocation.
+                if (string.IsNullOrEmpty(assemblyLocation))
+                {
+                    return null;
+                }
+
+                var xmlDocumentationFile = GetXmlDocumentationFile(assembly, assemblyLocation);
+
+                // Only want to process the file if it exists.
+                if (xmlDocumentationFile != null)
+                {
+                    return new XmlDocumentationProvider(xmlDocumentationFile.FullName);
+                }
 
-            // Couldn't resolve a valid assemblyLocation.
-            if (string.IsNullOrEmpty(assemblyLocation))
-            {
                 return null;
-            }
+            });
 
-            var xmlDocumentationFile = GetXmlDocumentationFile(assembly, assemblyLocation);
+            return documentationProvider;
+        }
 
-            // Only want to process the file if it exists.
-            if (xmlDocumentationFile != null)
+        private DocumentationDescriptor CreateDocumentationDescriptor(Assembly assembly, string id)
+        {
+            var documentationProvider = GetXmlDocumentationProvider(assembly);
+
+            if (documentationProvider != null)
             {
-                var documentationProvider = new XmlDocumentationProvider(xmlDocumentationFile.FullName);
-
                 var summary = documentationProvider.GetSummary(id);
                 var remarks = documentationProvider.GetRemarks(id);
 
diff --git a/src/Microsoft.AspNet.Razor.Runtime/project.json b/src/Microsoft.AspNet.Razor.Runtime/project.json
index 6c6f552f35..1c8f2f4d7e 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/project.json
+++ b/src/Microsoft.AspNet.Razor.Runtime/project.json
@@ -26,6 +26,12 @@
       "frameworkAssemblies": {
         "System.Xml": "4.0.0.0",
         "System.Xml.Linq": "4.0.0.0"
+      },
+      "dependencies": {
+        "Microsoft.Extensions.HashCodeCombiner.Sources": {
+          "type": "build",
+          "version": "1.0.0-*"
+        }
       }
     },
     "dotnet5.4": {
diff --git a/test/Microsoft.AspNet.Razor.Runtime.Precompilation.Test/PrecompilationTagHelperDescriptorFactoryTest.cs b/test/Microsoft.AspNet.Razor.Runtime.Precompilation.Test/PrecompilationTagHelperDescriptorFactoryTest.cs
index 9fad425be0..b1da983372 100644
--- a/test/Microsoft.AspNet.Razor.Runtime.Precompilation.Test/PrecompilationTagHelperDescriptorFactoryTest.cs
+++ b/test/Microsoft.AspNet.Razor.Runtime.Precompilation.Test/PrecompilationTagHelperDescriptorFactoryTest.cs
@@ -37,12 +37,12 @@ namespace Microsoft.AspNet.Razor.Runtime.Precompilation
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
diff --git a/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/RuntimeTagHelperDescriptorFactoryTest.cs b/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/RuntimeTagHelperDescriptorFactoryTest.cs
index 78d88a4842..d25c28939f 100644
--- a/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/RuntimeTagHelperDescriptorFactoryTest.cs
+++ b/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/RuntimeTagHelperDescriptorFactoryTest.cs
@@ -25,12 +25,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             var objectAssemblyName = typeof(object).GetTypeInfo().Assembly.GetName().Name;
             var expectedDescriptor =
                 CreateTagHelperDescriptor("object", "System.Object", objectAssemblyName);
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 objectAssemblyName,
                 GetTypeInfo(typeof(object)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -48,12 +48,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -137,12 +137,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: true);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime: true,
                 errorSink: errorSink);
 
             // Assert
diff --git a/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDescriptorFactoryTest.cs b/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDescriptorFactoryTest.cs
index b2df198292..4a396613b3 100644
--- a/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDescriptorFactoryTest.cs
+++ b/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDescriptorFactoryTest.cs
@@ -88,12 +88,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -177,12 +177,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -262,12 +262,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -351,12 +351,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -587,12 +587,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime,
                 errorSink);
 
             // Assert
@@ -789,12 +789,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -838,12 +838,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(tagHelperType),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -875,12 +875,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                         CreateTagHelperAttributeDescriptor("Something-Else", validProperty2)
                     })
             };
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(OverriddenAttributeTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -909,12 +909,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                         CreateTagHelperAttributeDescriptor("Something-Else", validProperty2)
                     })
             };
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(InheritedOverriddenAttributeTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -943,12 +943,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                         CreateTagHelperAttributeDescriptor("Something-Else", validProperty2)
                     })
             };
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(InheritedNotOverriddenAttributeTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
             // Assert
             Assert.Empty(errorSink.Errors);
@@ -973,12 +973,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                         TypeName = typeof(int).FullName
                     }
                 });
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(InheritedSingleAttributeTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -1001,12 +1001,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 {
                     CreateTagHelperAttributeDescriptor("int-attribute", intProperty)
                 });
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(SingleAttributeTagHelper)),
-                designTime: false,
                 errorSink: new ErrorSink());
 
             // Assert
@@ -1030,12 +1030,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 {
                     CreateTagHelperAttributeDescriptor("valid-attribute", validProperty)
                 });
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(MissingAccessorTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -1059,12 +1059,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 {
                     CreateTagHelperAttributeDescriptor("valid-attribute", validProperty)
                 });
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(NonPublicAccessorTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -1091,12 +1091,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                         TypeName = typeof(object).FullName
                     }
                 });
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(NotBoundAttributeTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -1110,12 +1110,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(DuplicateAttributeNameTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -1159,12 +1159,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                         }
                     })
             };
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(MultiTagTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -1191,12 +1191,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                     {
                         CreateTagHelperAttributeDescriptor("valid-attribute", validProp)
                     });
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(InheritedMultiTagTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -1221,12 +1221,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                     typeof(DuplicateTagNameTagHelper).FullName,
                     AssemblyName)
             };
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(DuplicateTagNameTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -1251,12 +1251,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                     typeof(OverrideNameTagHelper).FullName,
                     AssemblyName),
             };
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(typeof(OverrideNameTagHelper)),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
@@ -1439,12 +1439,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             var errorSink = new ErrorSink();
+            var factory = new TagHelperDescriptorFactory(designTime: false);
 
             // Act
-            var descriptors = TagHelperDescriptorFactory.CreateDescriptors(
+            var descriptors = factory.CreateDescriptors(
                 AssemblyName,
                 GetTypeInfo(type),
-                designTime: false,
                 errorSink: errorSink);
 
             // Assert
diff --git a/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDescriptorResolverTest.cs b/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDescriptorResolverTest.cs
index 3dcfcfc69f..ca6241f0f0 100644
--- a/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDescriptorResolverTest.cs
+++ b/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDescriptorResolverTest.cs
@@ -1381,7 +1381,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         private class TestTagHelperDescriptorResolver : TagHelperDescriptorResolver
         {
             public TestTagHelperDescriptorResolver(TagHelperTypeResolver typeResolver)
-                : base(typeResolver, designTime: false)
+                : base(typeResolver, new TagHelperDescriptorFactory(designTime: false))
             {
             }
 
diff --git a/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactoryTest.cs b/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactoryTest.cs
index 31d581c75c..e454f92223 100644
--- a/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactoryTest.cs
+++ b/test/Microsoft.AspNet.Razor.Runtime.Test/Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactoryTest.cs
@@ -74,8 +74,11 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             Type tagHelperType,
             TagHelperDesignTimeDescriptor expectedDescriptor)
         {
+            // Arrange
+            var factory = new TagHelperDesignTimeDescriptorFactory();
+
             // Act
-            var descriptors = TagHelperDesignTimeDescriptorFactory.CreateDescriptor(tagHelperType);
+            var descriptors = factory.CreateDescriptor(tagHelperType);
 
             // Assert
             Assert.Equal(expectedDescriptor, descriptors, TagHelperDesignTimeDescriptorComparer.Default);
@@ -142,8 +145,11 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             Type tagHelperType,
             TagHelperDesignTimeDescriptor expectedDesignTimeDescriptor)
         {
+            // Arrange
+            var factory = new TagHelperDesignTimeDescriptorFactory();
+
             // Act
-            var designTimeDescriptor = TagHelperDesignTimeDescriptorFactory.CreateDescriptor(tagHelperType);
+            var designTimeDescriptor = factory.CreateDescriptor(tagHelperType);
 
             // Assert
             Assert.Equal(expectedDesignTimeDescriptor, designTimeDescriptor, TagHelperDesignTimeDescriptorComparer.Default);
@@ -219,17 +225,59 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         {
             // Arrange
             TagHelperDesignTimeDescriptor designTimeDescriptor;
+            var factory = new TagHelperDesignTimeDescriptorFactory();
 
             // Act
             using (new CultureReplacer(culture))
             {
-                designTimeDescriptor = TagHelperDesignTimeDescriptorFactory.CreateDescriptor(tagHelperType);
+                designTimeDescriptor = factory.CreateDescriptor(tagHelperType);
             }
 
             // Assert
             Assert.Equal(expectedDesignTimeDescriptor, designTimeDescriptor, TagHelperDesignTimeDescriptorComparer.Default);
         }
 
+        [Fact]
+        public void CreateDescriptor_WithLocalizedType_CachesBasedOnCulture()
+        {
+            // Arrange
+            var factory = new TagHelperDesignTimeDescriptorFactory();
+            var expectedFRDesignTimeDescriptor = new TagHelperDesignTimeDescriptor
+            {
+                Summary = "fr-FR: " + TypeSummary,
+                Remarks = "fr-FR: " + TypeRemarks,
+                OutputElementHint = "p",
+            };
+            var expectedNLBEDesignTimeDescriptor = new TagHelperDesignTimeDescriptor
+            {
+                Summary = "nl-BE: " + TypeSummary,
+                Remarks = "nl-BE: " + TypeRemarks,
+                OutputElementHint = "p",
+            };
+            var tagHelperType = CreateDocumentationTagHelperType(LocalizedDocumentedAssemblyLocation, codeBase: null);
+            TagHelperDesignTimeDescriptor frDesignTimeDescriptor, nlBEDesignTimeDescriptor;
+
+            // Act
+            using (new CultureReplacer("fr-FR"))
+            {
+                frDesignTimeDescriptor = factory.CreateDescriptor(tagHelperType);
+            }
+            using (new CultureReplacer("nl-BE"))
+            {
+                nlBEDesignTimeDescriptor = factory.CreateDescriptor(tagHelperType);
+            }
+
+            // Assert
+            Assert.Equal(
+                expectedFRDesignTimeDescriptor,
+                frDesignTimeDescriptor,
+                TagHelperDesignTimeDescriptorComparer.Default);
+            Assert.Equal(
+                expectedNLBEDesignTimeDescriptor,
+                nlBEDesignTimeDescriptor,
+                TagHelperDesignTimeDescriptorComparer.Default);
+        }
+
         public static TheoryData CreateAttributeDescriptor_PropertyDocumentationData
         {
             get
@@ -374,9 +422,10 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             var mockPropertyInfo = new Mock<PropertyInfo>();
             mockPropertyInfo.Setup(propertyInfo => propertyInfo.DeclaringType).Returns(tagHelperType);
             mockPropertyInfo.Setup(propertyInfo => propertyInfo.Name).Returns(propertyName);
+            var factory = new TagHelperDesignTimeDescriptorFactory();
 
             // Act
-            var designTimeDescriptor = TagHelperDesignTimeDescriptorFactory.CreateAttributeDescriptor(
+            var designTimeDescriptor = factory.CreateAttributeDescriptor(
                 mockPropertyInfo.Object);
 
             // Assert
@@ -456,11 +505,12 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 .Setup(propertyInfo => propertyInfo.Name)
                 .Returns(nameof(DocumentedTagHelper.RemarksAndSummaryProperty));
             TagHelperAttributeDesignTimeDescriptor designTimeDescriptor;
+            var factory = new TagHelperDesignTimeDescriptorFactory();
 
             // Act
             using (new CultureReplacer(culture))
             {
-                designTimeDescriptor = TagHelperDesignTimeDescriptorFactory.CreateAttributeDescriptor(
+                designTimeDescriptor = factory.CreateAttributeDescriptor(
                     mockPropertyInfo.Object);
             }
 
@@ -471,6 +521,50 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
                 TagHelperAttributeDesignTimeDescriptorComparer.Default);
         }
 
+        [Fact]
+        public void CreateDescriptor_WithLocalizedProperty_CachesBasedOnCulture()
+        {
+            // Arrange
+            var tagHelperType = CreateDocumentationTagHelperType(LocalizedDocumentedAssemblyLocation, codeBase: null);
+            var mockPropertyInfo = new Mock<PropertyInfo>();
+            mockPropertyInfo.Setup(propertyInfo => propertyInfo.DeclaringType).Returns(tagHelperType);
+            mockPropertyInfo
+                .Setup(propertyInfo => propertyInfo.Name)
+                .Returns(nameof(DocumentedTagHelper.RemarksAndSummaryProperty));
+            var factory = new TagHelperDesignTimeDescriptorFactory();
+            var expectedFRDesignTimeDescriptor = new TagHelperAttributeDesignTimeDescriptor
+            {
+                Summary = "fr-FR: " + PropertyWithSummaryAndRemarks_Summary,
+                Remarks = "fr-FR: " + PropertyWithSummaryAndRemarks_Remarks
+            };
+            var expectedNLBEDesignTimeDescriptor = new TagHelperAttributeDesignTimeDescriptor
+            {
+                Summary = "nl-BE: " + PropertyWithSummaryAndRemarks_Summary,
+                Remarks = "nl-BE: " + PropertyWithSummaryAndRemarks_Remarks
+            };
+            TagHelperAttributeDesignTimeDescriptor frDesignTimeDescriptor, nlBEDesignTimeDescriptor;
+
+            // Act
+            using (new CultureReplacer("fr-FR"))
+            {
+                frDesignTimeDescriptor = factory.CreateAttributeDescriptor(mockPropertyInfo.Object);
+            }
+            using (new CultureReplacer("nl-BE"))
+            {
+                nlBEDesignTimeDescriptor = factory.CreateAttributeDescriptor(mockPropertyInfo.Object);
+            }
+
+            // Assert
+            Assert.Equal(
+                expectedFRDesignTimeDescriptor,
+                frDesignTimeDescriptor,
+                TagHelperAttributeDesignTimeDescriptorComparer.Default);
+            Assert.Equal(
+                expectedNLBEDesignTimeDescriptor,
+                nlBEDesignTimeDescriptor,
+                TagHelperAttributeDesignTimeDescriptorComparer.Default);
+        }
+
         private static Type CreateDocumentationTagHelperType(string location, string codeBase)
         {
             return CreateType<DocumentedTagHelper>(location, codeBase);
diff --git a/test/Microsoft.AspNet.Razor.Runtime.Test/project.json b/test/Microsoft.AspNet.Razor.Runtime.Test/project.json
index 18f5b77b49..485a4d1d9d 100644
--- a/test/Microsoft.AspNet.Razor.Runtime.Test/project.json
+++ b/test/Microsoft.AspNet.Razor.Runtime.Test/project.json
@@ -11,10 +11,6 @@
       "type": "build"
     },
     "Microsoft.AspNet.Testing": "1.0.0-*",
-    "Microsoft.Extensions.HashCodeCombiner.Sources": {
-      "type": "build",
-      "version": "1.0.0-*"
-    },
     "Microsoft.Extensions.WebEncoders": "1.0.0-*",
     "xunit.runner.aspnet": "2.0.0-aspnet-*"
   },
@@ -27,6 +23,13 @@
         "Moq": "4.2.1312.1622"
       }
     },
-    "dnxcore50": {}
+    "dnxcore50": {
+      "dependencies": {
+        "Microsoft.Extensions.HashCodeCombiner.Sources": {
+          "type": "build",
+          "version": "1.0.0-*"
+        }
+      }
+    }
   }
 }