[Cast] VideoFrameFactory interface to vend frames with encoder affinity.

media/cast/sender/video_frame_factory_pool_impl.cc

+// Copyright 2014 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/cast/sender/video_frame_factory_pool_impl.h"
+
+namespace media {
+namespace cast {
+
+VideoFrameFactoryPoolImpl::VideoFrameFactoryPoolImpl(
+    const VideoSenderConfig& video_config)
+    : width_(video_config.width), height_(video_config.height) {
+}
+
+scoped_refptr<VideoFrame> VideoFrameFactoryPoolImpl::CreateFrame(
+    base::TimeDelta timestamp) {
+  return pool_.CreateFrame(VideoFrame::Format::I420,
+                           gfx::Size(width_, height_),
+                           gfx::Rect(0, 0, width_, height_),
+                           gfx::Size(width_, height_),
+                           timestamp);
+}
+
+}  // namespace cast
+}  // namespace media