Support configuration changes in VTVideoDecodeAccelerator.

content/common/gpu/media/vt_video_decode_accelerator.h

Index: content/common/gpu/media/vt_video_decode_accelerator.h
diff --git a/content/common/gpu/media/vt_video_decode_accelerator.h b/content/common/gpu/media/vt_video_decode_accelerator.h
index d3850d87489e6cc9de5cf74f301ac873eabe59de..5aa4f7051c7cabb40c36587263e72cff71f86c41 100644
--- a/content/common/gpu/media/vt_video_decode_accelerator.h
+++ b/content/common/gpu/media/vt_video_decode_accelerator.h
@@ -92,13 +92,25 @@ class VTVideoDecodeAccelerator
 
   // Methods for interacting with |client_|. Run on |gpu_task_runner_|.
   void OutputTask(DecodedFrame frame);
-  void SizeChangedTask(gfx::Size coded_size);
   void NotifyError(Error error);
 
   // Send decoded frames up to and including |up_to_bitstream_id|, and return
   // the last sent |bitstream_id|.
   int32_t SendPictures(int32_t up_to_bitstream_id);
 
+  // Internal helper for SendPictures(): Drop frames with no image data up to
+  // a particular bitstream ID, so that if there is still a frame in the queue
+  // when this function returns, it is guaranteed to have image data, and thus
+  // it is time to set up the GPU context. Returns the last bitstream ID that
+  // was dropped, or |last_sent_bitstream_id| if no frames were dropped.
+  int32_t ProcessDroppedFrames(
+      int32_t last_sent_bitstream_id,
+      int32_t up_to_bitstream_id);
+
+  // Internal helper for SendPictures(): Check if the next frame has a size
+  // different from the current picture buffers, and request new ones if so.
+  void ProcessSizeChangeIfNeeded();
+
   // Since VideoToolbox has no reset feature (only flush), and the VDA API
   // allows Decode() and Flush() calls during a reset operation, it's possible
   // to have multiple pending actions at once. We handle the fully general case
@@ -125,17 +137,32 @@ class VTVideoDecodeAccelerator
   CGLContextObj cgl_context_;
   base::Callback<bool(void)> make_context_current_;
   media::VideoDecodeAccelerator::Client* client_;
-  bool has_error_;  // client_->NotifyError() called.
-  gfx::Size texture_size_;
+
+  // client_->NotifyError() called.
+  bool has_error_;
+
+  // Size of assigned picture buffers.
+  gfx::Size picture_size_;
+
+  // Queue of actions so that we can quickly discover what the next action will
+  // be; this is useful because we are dropping all frames when the next action
+  // is ACTION_RESET or ACTION_DESTROY.
   std::queue<PendingAction> pending_actions_;
+
+  // Queue of bitstreams that have not yet been decoded. This is mostly needed
+  // to be sure we free them all in Destroy().
   std::queue<int32_t> pending_bitstream_ids_;
 
-  // Texture IDs of pictures.
-  // TODO(sandersd): A single map of structs holding picture data.
+  // All picture buffers assigned to us. Used to check if reused picture buffers
+  // should be added back to the available list or released. (They are not
+  // released immediately because we need the reuse event to free the binding.)
+  std::set<int32_t> assigned_picture_ids_;
+
+  // Texture IDs of assigned pictures.
   std::map<int32_t, uint32_t> texture_ids_;
 
   // Pictures ready to be rendered to.
-  std::queue<int32_t> available_picture_ids_;
+  std::vector<int32_t> available_picture_ids_;
 
   // Decoded frames ready to render.
   std::queue<DecodedFrame> decoded_frames_;
@@ -150,7 +177,10 @@ class VTVideoDecodeAccelerator
   base::ScopedCFTypeRef<CMFormatDescriptionRef> format_;
   base::ScopedCFTypeRef<VTDecompressionSessionRef> session_;
   media::H264Parser parser_;
-  gfx::Size coded_size_;
+
+  std::vector<uint8_t> last_sps_;
+  std::vector<uint8_t> last_spsext_;
+  std::vector<uint8_t> last_pps_;
 
   //
   // Shared state (set up and torn down on GPU thread).