The project snapshot now maintains a RazorProjectEngine as well as set
of Tag Helpers that are known for that snapshot.
Pivoted some more services to be snapshot-centric.
Also added the ability to track .cshtml documents to the project system.
For now most components just ignore document changes.
- Updated the a `VisualStudioWorkspaceAccessor` API in windows to enable the factory to retrieve a workspace given a text buffer.
- Added a way to add test services to `AdhocWorkspace` so we can test against services being retrieved from a `Workspace`. This will be much more common once we rely on services coming from `TextBuffer`s in our other tooling pieces.
- Added tests for the default workspace provider.
#1989
- Created a new `TestWorkspace` type to lock on `AdhocWorkspace` construction. This type can't be constructed/changed in parallel.
- Updated test usages of `AdhocWorkspace` to make use of `TestWorkspace`.
- Added a `Microsoft.CodeAnalysis.Razor.Workspaces.Test.Common` project to have the `TestWorkspace` type.
#1913
Pranav K
N. Taylor Mullen
Ryan Nowak