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

media/base/video_frame.cc

 // 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.
 
 #include "media/base/video_frame.h"
 
 #include "base/logging.h"
 #include "base/string_piece.h"
 #include "media/base/limits.h"
 #include "media/base/video_util.h"
@@ skipping 43 matching lines @@
           natural_size.width() * natural_size.height() <= limits::kMaxCanvas);
 }
 
 // static
 scoped_refptr<VideoFrame> VideoFrame::WrapNativeTexture(
     uint32 texture_id,
     uint32 texture_target,
     const gfx::Size& data_size,
     const gfx::Size& natural_size,
     base::TimeDelta timestamp,
+    const ReadPixelsCB& read_pixels_cb,
     const base::Closure& no_longer_needed) {
   scoped_refptr<VideoFrame> frame(
       new VideoFrame(NATIVE_TEXTURE, data_size, natural_size, timestamp));
   frame->texture_id_ = texture_id;
   frame->texture_target_ = texture_target;
+  frame->read_pixels_cb_ = read_pixels_cb;
   frame->texture_no_longer_needed_ = no_longer_needed;
   return frame;
 }
 
+void VideoFrame::ReadPixelsFromNativeTexture(void* pixels) {
+  DCHECK_EQ(format_, NATIVE_TEXTURE);
+  if (!read_pixels_cb_.is_null())
+    read_pixels_cb_.Run(pixels);
+}
+
 // static
 scoped_refptr<VideoFrame> VideoFrame::CreateEmptyFrame() {
   return new VideoFrame(
       VideoFrame::EMPTY, gfx::Size(), gfx::Size(), base::TimeDelta());
 }
 
 // static
 scoped_refptr<VideoFrame> VideoFrame::CreateBlackFrame(
     const gfx::Size& data_size) {
   DCHECK(IsValidConfig(VideoFrame::YV12, data_size, data_size));
@@ skipping 213 matching lines @@
       break;
     for(int row = 0; row < rows(plane); row++) {
       base::MD5Update(context, base::StringPiece(
           reinterpret_cast<char*>(data(plane) + stride(plane) * row),
           row_bytes(plane)));
     }
   }
 }
 
 }  // namespace media