[Cast] Size-Adaptable platform video encoders.

media/cast/sender/video_encoder.h

 // 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.
 
 #ifndef MEDIA_CAST_SENDER_VIDEO_ENCODER_H_
 #define MEDIA_CAST_SENDER_VIDEO_ENCODER_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "media/base/video_frame.h"
 #include "media/cast/cast_config.h"
 #include "media/cast/cast_environment.h"
+#include "media/cast/sender/video_frame_factory.h"
 
 namespace media {
 namespace cast {
 
-class VideoFrameFactory;
-
 // All these functions are called from the main cast thread.
 class VideoEncoder {
  public:
   typedef base::Callback<void(scoped_ptr<EncodedFrame>)> FrameEncodedCallback;
 
+  // Creates a VideoEncoder instance from the given |video_config| and based on
+  // the current platform's hardware/library support; or null if no
+  // implementation will suffice.  The instance will run |status_change_cb| at
+  // some point in the future to indicate initialization success/failure.
+  //
+  // All VideoEncoder instances returned by this function support encoding
+  // sequences of differently-size VideoFrames.
+  //
+  // TODO(miu): Remove the CreateVEA callbacks.  http://crbug.com/454029
+  static scoped_ptr<VideoEncoder> Create(
+      const scoped_refptr<CastEnvironment>& cast_environment,
+      const VideoSenderConfig& video_config,
+      const StatusChangeCallback& status_change_cb,
+      const CreateVideoEncodeAcceleratorCallback& create_vea_cb,
+      const CreateVideoEncodeMemoryCallback& create_video_encode_memory_cb);
+
   virtual ~VideoEncoder() {}
 
-  // Returns true if the size of video frames passed in successive calls to
-  // EncodedVideoFrame() can vary.
-  virtual bool CanEncodeVariedFrameSizes() const = 0;
-
   // If true is returned, the Encoder has accepted the request and will process
   // it asynchronously, running |frame_encoded_callback| on the MAIN
   // CastEnvironment thread with the result.  If false is returned, nothing
   // happens and the callback will not be run.
   virtual bool EncodeVideoFrame(
       const scoped_refptr<media::VideoFrame>& video_frame,
       const base::TimeTicks& reference_time,
       const FrameEncodedCallback& frame_encoded_callback) = 0;
 
   // Inform the encoder about the new target bit rate.
@@ skipping 16 matching lines @@
   // network congestion, it is necessary to flush out of the encoder all
   // submitted frames so that eventually new frames may be encoded. Like
   // EncodeVideoFrame(), the encoder will process this request asynchronously.
   virtual void EmitFrames();
 };
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_SENDER_VIDEO_ENCODER_H_