Create new way of suppressing unique Id generation

Adds a way of suppressing generation of guid ids that isn't based on a
global static.

src/Microsoft.AspNetCore.Razor.Evolution/DefaultRazorRuntimeCSharpLoweringPhase.cs

@@ -12,18 +12,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
 {
     internal class DefaultRazorRuntimeCSharpLoweringPhase : RazorCSharpLoweringPhaseBase
     {
-        private static string _tagHelperId;
+        internal static readonly object SuppressUniqueIds = "SuppressUniqueIds";
-
-        internal static string GenerateUniqueTagHelperId {
-            get
-            {
-                return _tagHelperId ?? Guid.NewGuid().ToString("N");
-            }
-            set
-            {
-                _tagHelperId = value;
-            }
-        }
 
         protected override void ExecuteCore(RazorCodeDocument codeDocument)
         {
@@ -39,6 +28,13 @@ namespace Microsoft.AspNetCore.Razor.Evolution
                 SourceDocument = codeDocument.Source,
                 Options = syntaxTree.Options,
             };
+
+            var idValue = codeDocument.Items[SuppressUniqueIds];
+            if (idValue != null)
+            {
+                renderingContext.IdGenerator = () => idValue.ToString();
+            }
+
             var visitor = new CSharpRenderer(renderingContext);
             visitor.VisitDocument(irDocument);
             var csharpDocument = new RazorCSharpDocument()
@@ -300,7 +296,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
                     .Write(".")
                     .Write(node.TagMode.ToString())
                     .WriteParameterSeparator()
-                    .WriteStringLiteral(GenerateUniqueTagHelperId)
+                    .WriteStringLiteral(Context.IdGenerator())
                     .WriteParameterSeparator();
 
                 // We remove and redirect writers so TagHelper authors can retrieve content.

src/Microsoft.AspNetCore.Razor.Evolution/RazorCSharpLoweringPhaseBase.cs

@@ -189,6 +189,8 @@ namespace Microsoft.AspNetCore.Razor.Evolution
 
             public ICollection<DirectiveDescriptor> Directives { get; set; }
 
+            public Func<string> IdGenerator { get; set; } = () => Guid.NewGuid().ToString("N");
+
             public List<LineMapping> LineMappings { get; } = new List<LineMapping>();
 
             public CSharpCodeWriter Writer { get; set; }

test/Microsoft.AspNetCore.Razor.Evolution.Test/IntegrationTests/CodeGenerationIntegrationTest.cs

@@ -1408,7 +1408,11 @@ namespace Microsoft.AspNetCore.Razor.Evolution.IntegrationTests
                 throw new XunitException($"The resource {sourceFilename} was not found.");
             }
 
-            return RazorCodeDocument.Create(TestRazorSourceDocument.CreateResource(sourceFilename));
+            var codeDocument = RazorCodeDocument.Create(TestRazorSourceDocument.CreateResource(sourceFilename));
+
+            // This will ensure that we're not putting any randomly generated data in a baseline.
+            codeDocument.Items[DefaultRazorRuntimeCSharpLoweringPhase.SuppressUniqueIds] = "test";
+            return codeDocument;
         }
 
         private void RunRuntimeTagHelpersTest(IEnumerable<TagHelperDescriptor> descriptors)

test/Microsoft.AspNetCore.Razor.Evolution.Test/IntegrationTests/IntegrationTestBase.cs

@@ -88,10 +88,11 @@ namespace Microsoft.AspNetCore.Razor.Evolution.IntegrationTests
                 throw new XunitException($"The resource {sourceFilename} was not found.");
             }
 
-            // This will ensure that we're not putting any randomly generated data in a baseline.
+            var codeDocument = RazorCodeDocument.Create(TestRazorSourceDocument.CreateResource(sourceFilename));
-            DefaultRazorRuntimeCSharpLoweringPhase.GenerateUniqueTagHelperId = "test";
 
-            return RazorCodeDocument.Create(TestRazorSourceDocument.CreateResource(sourceFilename));
+            // This will ensure that we're not putting any randomly generated data in a baseline.
+            codeDocument.Items[DefaultRazorRuntimeCSharpLoweringPhase.SuppressUniqueIds] = "test";
+            return codeDocument;
         }
 
         protected void AssertIRMatchesBaseline(DocumentIRNode document)