Bug 1470977 - Fix GLBlitHelperD3D.cpp mingw clang compilation r=lsalzman

MozReview-Commit-ID: IbOPAYoYJjj

--HG--
extra : rebase_source : f800779bdb4b2c9b782d10094c329774eb377705

gfx/gl/GLBlitHelperD3D.cpp

@@ -184,12 +184,12 @@ GLBlitHelper::BlitImage(layers::GPUVideoImage* const srcImage,
     const auto& desc = data->SD();
     const auto& subdescUnion = desc.subdesc();
     switch (subdescUnion.type()) {
-    case subdescUnion.TSurfaceDescriptorD3D10:
+    case layers::SurfaceDescriptor::TSurfaceDescriptorD3D10:
         {
             const auto& subdesc = subdescUnion.get_SurfaceDescriptorD3D10();
             return BlitDescriptor(subdesc, destSize, destOrigin);
         }
-    case subdescUnion.TSurfaceDescriptorDXGIYCbCr:
+    case layers::SurfaceDescriptor::TSurfaceDescriptorDXGIYCbCr:
         {
             const auto& subdesc = subdescUnion.get_SurfaceDescriptorDXGIYCbCr();
 
@@ -224,9 +224,6 @@ GLBlitHelper::BlitImage(layers::D3D11YCbCrImage* const srcImage,
     if (!data)
         return false;
 
-    const auto& clipRect = srcImage->mPictureRect;
-    const auto& colorSpace = srcImage->mColorSpace;
-
     const WindowsHandle handles[3] = {
         (WindowsHandle)data->mHandles[0],
         (WindowsHandle)data->mHandles[1],