media: Remove kD3D11VideoDecoding feature

This feature is not used anywhere.

Also fix some if/def comments related to D3D11.

Change-Id: If7b37e88e0a1e8e12d9e55667eef17cc67703fae
Reviewed-on: https://chromium-review.googlesource.com/954415Reviewed-by: Frank Liberato <liberato@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541822}

media/base/media_switches.cc

@@ -319,11 +319,6 @@ const base::Feature kMediaDrmPersistentLicense{
 #endif
 
 #if defined(OS_WIN)
-// Enables video decode acceleration using the D3D11 video decoder api.
-// This is completely insecure - DO NOT USE except for testing.
-const base::Feature kD3D11VideoDecoding{"D3D11VideoDecoding",
-                                        base::FEATURE_DISABLED_BY_DEFAULT};
-
 // Does NV12->NV12 video copy on the main thread right before the texture's
 // used by GL.
 const base::Feature kDelayCopyNV12Textures{"DelayCopyNV12Textures",

media/base/media_switches.h

@@ -145,7 +145,6 @@ MEDIA_EXPORT extern const base::Feature kMediaDrmPersistentLicense;
 #endif  // defined(OS_ANDROID)
 
 #if defined(OS_WIN)
-MEDIA_EXPORT extern const base::Feature kD3D11VideoDecoding;
 MEDIA_EXPORT extern const base::Feature kDelayCopyNV12Textures;
 MEDIA_EXPORT extern const base::Feature kMediaFoundationH264Encoding;
 MEDIA_EXPORT extern const base::Feature kMediaFoundationVideoCapture;

media/mojo/services/gpu_mojo_media_client.cc

@@ -77,7 +77,7 @@ gpu::CommandBufferStub* GetCommandBufferStub(
 
   return channel->LookupCommandBuffer(route_id);
 }
-#endif  // OS_ANDROID || BUILDFLAG(ENABLE_MEDIA_CODEC_VIDEO_D3D11)
+#endif  // OS_ANDROID || (OS_WIN && BUILDFLAG(ENABLE_D3D11_VIDEO_DECODER))
 
 }  // namespace
 
@@ -131,7 +131,7 @@ std::unique_ptr<VideoDecoder> GpuMojoMediaClient::CreateVideoDecoder(
                           command_buffer_id->route_id));
 #else
   return nullptr;
-#endif  // BUILDFLAG(ENABLE_{MEDIA_CODEC | D3D11}_VIDEO_DECODER)
+#endif  // defined(OS_ANDROID)
 }
 
 std::unique_ptr<CdmFactory> GpuMojoMediaClient::CreateCdmFactory(