[chrome.displaySource] Implement software based H.264 video encoder.

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

Index: extensions/renderer/api/display_source/wifi_display/wifi_display_video_encoder.h
diff --git a/extensions/renderer/api/display_source/wifi_display/wifi_display_video_encoder.h b/extensions/renderer/api/display_source/wifi_display/wifi_display_video_encoder.h
index d992d4742f9ce0c668d638519f7e85ad9a6e520c..d2ff86a58641d8083b69f649ca3e145111564fa1 100644
--- a/extensions/renderer/api/display_source/wifi_display/wifi_display_video_encoder.h
+++ b/extensions/renderer/api/display_source/wifi_display/wifi_display_video_encoder.h
@@ -65,10 +65,18 @@ class WiFiDisplayVideoEncoder : public WiFiDisplayMediaEncoder {
   void RequestIDRPicture();
 
  protected:
+  // A factory method that creates a new encoder instance which uses OpenH264
+  // SVC encoder for encoding.
+  static void CreateSVC(const InitParameters& params,
+                        const VideoEncoderCallback& encoder_callback);
+
   // 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);
+  static void OnCreatedVEA(const InitParameters& params,
+                           const VideoEncoderCallback& encoder_callback,
+                           scoped_refptr<WiFiDisplayVideoEncoder> vea_encoder);
 
   explicit WiFiDisplayVideoEncoder(
       scoped_refptr<base::SingleThreadTaskRunner> media_task_runner);