Revert of Revert of Remove threading from RendererGpuVideoAcceleratorFactories

media/filters/gpu_video_accelerator_factories.h

Index: media/filters/gpu_video_accelerator_factories.h
diff --git a/media/filters/gpu_video_accelerator_factories.h b/media/filters/gpu_video_accelerator_factories.h
index b6de58f4a239d2b22eee8a21b5435f9c4754cf7c..88d74b57aef2b3fdcedb2448dc3fe1d44dd84a8c 100644
--- a/media/filters/gpu_video_accelerator_factories.h
+++ b/media/filters/gpu_video_accelerator_factories.h
@@ -21,6 +21,12 @@
 
 // Helper interface for specifying factories needed to instantiate a hardware
 // video accelerator.
+// Threading model:
+// * The GpuVideoAcceleratorFactories may be constructed on any thread.
+// * The GpuVideoAcceleratorFactories has an associated message loop, which may
+//   be retrieved as |GetMessageLoop()|.
+// * All calls to the Factories after construction must be made on its message
+//   loop.
 class MEDIA_EXPORT GpuVideoAcceleratorFactories
     : public base::RefCountedThreadSafe<GpuVideoAcceleratorFactories> {
  public:
@@ -43,9 +49,10 @@
 
   virtual void WaitSyncPoint(uint32 sync_point) = 0;
 
-  // Read pixels from a native texture and store into |pixels| as RGBA.
+  // Read pixels within |visible_rect| boundaries from a native texture and
+  // store into |pixels| as RGBA.
   virtual void ReadPixels(uint32 texture_id,
-                          const gfx::Size& size,
+                          const gfx::Rect& visible_rect,
                           const SkBitmap& pixels) = 0;
 
   // Allocate & return a shared memory segment.  Caller is responsible for
@@ -55,13 +62,6 @@
   // Returns the task runner the video accelerator runs on.
   virtual scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() = 0;
 
-  // Abort any outstanding factory operations and error any future
-  // attempts at factory operations
-  virtual void Abort() = 0;
-
-  // Returns true if Abort() has been called.
-  virtual bool IsAborted() = 0;
-
  protected:
   friend class base::RefCountedThreadSafe<GpuVideoAcceleratorFactories>;
   virtual ~GpuVideoAcceleratorFactories();