Don't require VDAs to return all PictureBuffers at once.

media/filters/gpu_video_decoder.h

Index: media/filters/gpu_video_decoder.h
diff --git a/media/filters/gpu_video_decoder.h b/media/filters/gpu_video_decoder.h
index 065ac38d068abecdea8bdc5b769fd6fbec54f915..aaa5225fa326c833d208ca71141c41d3779e7115 100644
--- a/media/filters/gpu_video_decoder.h
+++ b/media/filters/gpu_video_decoder.h
@@ -135,9 +135,12 @@ class MEDIA_EXPORT GpuVideoDecoder
   // Destroy all PictureBuffers in |buffers|, and delete their textures.
   void DestroyPictureBuffers(PictureBufferMap* buffers);
 
-  // Returns true if the video decoder can support |profile| and |coded_size|.
-  bool IsProfileSupported(VideoCodecProfile profile,
-                          const gfx::Size& coded_size);
+  // Returns true if the video decoder with |capabilities| can support
+  // |profile| and |coded_size|.
+  bool IsProfileSupported(
+      const VideoDecodeAccelerator::Capabilities& capabilities,
+      VideoCodecProfile profile,
+      const gfx::Size& coded_size);
 
   // Assert the contract that this class is operated on the right thread.
   void DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent() const;
@@ -203,6 +206,13 @@ class MEDIA_EXPORT GpuVideoDecoder
   // HasAvailableOutputFrames().
   int available_pictures_;
 
+  // If false, then we may assume that the VDA cannot stall sending picture
+  // buffers until all of them have decoded frames that have been delivered
+  // to the client.  If true, then the VDA may refuse to send more picture

[Pawel Osciak, 2015/12/09 01:31:49]

Hmm... What would you think about:

"If true, the client cannot expect the VDA to produce any new decoded frames,
until it returns all PictureBuffers it may be holding back to the VDA. In other
words, the VDA may require all PictureBuffers to be able to proceed with
decoding the next frame."

[liberato (no reviews please), 2015/12/09 22:15:31]

Done.

+  // buffers to the client if any picture buffer has been provided to the
+  // client that has not been reused or dismissed.
+  bool can_stall_anytime_;

[Pawel Osciak, 2015/12/09 01:31:49]

My point is, I feel that "anytime" doesn't help explain the issue. "Can stall"
already expresses "anytime" in my opinion.

How about calling it "needs_all_picture_buffers_to_decode_" ?

It is a bit of a mouthful, but expresses the issue precisely and we only use it
in one conditional.

[liberato (no reviews please), 2015/12/09 22:15:31]

Done.

+
   // Bound to factories_->GetMessageLoop().
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<GpuVideoDecoder> weak_factory_;