Support reading pixels from HW-decoded video textures into canvas/webgl.

media/filters/gpu_video_decoder.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_FILTERS_GPU_VIDEO_DECODER_H_
 #define MEDIA_FILTERS_GPU_VIDEO_DECODER_H_
 
 #include <list>
 #include <map>
 #include <utility>
@@ skipping 29 matching lines @@
     // Caller owns returned pointer.
     virtual VideoDecodeAccelerator* CreateVideoDecodeAccelerator(
         VideoCodecProfile, VideoDecodeAccelerator::Client*) = 0;
 
     // Allocate & delete native textures.
     virtual bool CreateTextures(int32 count, const gfx::Size& size,
                                 std::vector<uint32>* texture_ids,
                                 uint32 texture_target) = 0;
     virtual void DeleteTexture(uint32 texture_id) = 0;
 
+    // Read pixels from a native texture.

[Ken Russell (switch to Gerrit), 2012/10/01 17:56:16]

Again, document format of pixels.

[Ami GONE FROM CHROMIUM, 2012/10/01 18:16:12]

Done.

+    virtual void ReadPixels(uint32 texture_id, uint32 texture_target,
+                            const gfx::Size& size, void* pixels) = 0;
+
     // Allocate & return a shared memory segment.  Caller is responsible for
     // Close()ing the returned pointer.
     virtual base::SharedMemory* CreateSharedMemory(size_t size) = 0;
 
    protected:
     friend class base::RefCountedThreadSafe<Factories>;
     virtual ~Factories();
   };
 
   typedef base::Callback<
@@ skipping 159 matching lines @@
 
   // Indicates decoding error occurred.
   bool error_occured_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuVideoDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_GPU_VIDEO_DECODER_H_