[chrome.displaySource] Implement hardware accelerated H.264 video encoder.

extensions/renderer/api/display_source/wifi_display/wifi_display_video_encoder.h

 // Copyright 2016 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 EXTENSIONS_RENDERER_API_DISPLAY_SOURCE_WIFI_DISPLAY_WIFI_DISPLAY_VIDEO_ENCODER_H_
 #define EXTENSIONS_RENDERER_API_DISPLAY_SOURCE_WIFI_DISPLAY_WIFI_DISPLAY_VIDEO_ENCODER_H_
 
 #include "base/memory/shared_memory.h"
 #include "extensions/renderer/api/display_source/wifi_display/wifi_display_media_encoder.h"
 #include "media/base/video_frame.h"
@@ skipping 25 matching lines @@
 
   struct InitParameters {
     InitParameters();
     InitParameters(const InitParameters&);
     ~InitParameters();
     gfx::Size frame_size;
     int frame_rate;
     int bit_rate;
     wds::H264Profile profile;
     wds::H264Level level;
-    // VEA-specific parameters.
+    // Video Encode Accelerator (VEA) specific parameters.
     CreateEncodeMemoryCallback create_memory_callback;
     CreateVideoEncodeAcceleratorCallback vea_create_callback;
   };
 
   // A factory method that creates a new encoder instance from the given
   // |params|, the encoder instance is returned as an argument of
   // |result_callback| ('nullptr' argument means encoder creation failure).
   static void Create(const InitParameters& params,
                      const VideoEncoderCallback& encoder_callback);
 
   // Encodes the given raw frame. The resulting encoded frame is passed
   // as an |encoded_callback|'s argument which is set via 'SetCallbacks'
   // method.
   void InsertRawVideoFrame(const scoped_refptr<media::VideoFrame>& video_frame,
                            base::TimeTicks reference_time);
 
   // Requests the next encoded frame to be an instantaneous decoding refresh
   // (IDR) picture.
   void RequestIDRPicture();
 
  protected:
+  // A factory method that creates a new encoder instance which uses Video
+  // Encode Accelerator (VEA) for encoding.
+  static void CreateVEA(const InitParameters& params,
+                        const VideoEncoderCallback& encoder_callback);
+
   explicit WiFiDisplayVideoEncoder(
       scoped_refptr<base::SingleThreadTaskRunner> media_task_runner);
   ~WiFiDisplayVideoEncoder() override;
 
   virtual void InsertFrameOnMediaThread(
       scoped_refptr<media::VideoFrame> video_frame,
       base::TimeTicks reference_time,
       bool send_idr) = 0;
 
   scoped_refptr<base::SingleThreadTaskRunner> media_task_runner_;
   bool send_idr_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_API_DISPLAY_SOURCE_WIFI_DISPLAY_WIFI_DISPLAY_VIDEO_ENCODER_H_