Reland: H264 HW encode using VideoToolbox

media/cast/sender/h264_vt_encoder.h

Index: media/cast/sender/h264_vt_encoder.h
diff --git a/media/cast/sender/h264_vt_encoder.h b/media/cast/sender/h264_vt_encoder.h
index c3b414da8a60901600af19124d60fa9778f2022a..5371d4b32978a272f7778cf7237154694847271c 100644
--- a/media/cast/sender/h264_vt_encoder.h
+++ b/media/cast/sender/h264_vt_encoder.h
@@ -12,6 +12,7 @@
 #include "base/power_monitor/power_observer.h"
 #include "base/threading/thread_checker.h"
 #include "media/base/mac/videotoolbox_glue.h"
+#include "media/base/mac/videotoolbox_helpers.h"
 #include "media/cast/sender/size_adaptable_video_encoder_base.h"
 #include "media/cast/sender/video_encoder.h"
 
@@ -75,11 +76,6 @@ class H264VideoToolboxEncoder : public VideoEncoder,
   // session. This will also update the video frame factory.
   void UpdateFrameSize(const gfx::Size& size_needed);
 
-  // Set a compression session property.
-  bool SetSessionProperty(CFStringRef key, int32_t value);
-  bool SetSessionProperty(CFStringRef key, bool value);
-  bool SetSessionProperty(CFStringRef key, CFStringRef value);
-
   // Compression session callback function to handle compressed frames.
   static void CompressionCallback(void* encoder_opaque,
                                   void* request_opaque,