WGL implemetation for OpenGL tutorial Fixes to make WGL implementation work with OpenGL tutorial - Give directive parser the correct shader spec when on Desktop GL - Minor changes to parse Desktop GL shaders - Moved clientType parameter from Context to Context->mState - Minor fixes to WGL functions Bug: angleproject:3666 Change-Id: I01ddb828f6d581ad445f49942589436849eae5d9 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1693244 Commit-Queue: Clemen Deng <clemendeng@google.com> Reviewed-by: Geoff Lang <geofflang@chromium.org>