Reland: H264 HW encode using VideoToolbox

media/cast/sender/video_encoder.cc

Index: media/cast/sender/video_encoder.cc
diff --git a/media/cast/sender/video_encoder.cc b/media/cast/sender/video_encoder.cc
index 964a6c5867516f1c9c5640ef562cf26d281fcd23..ab1d56f2072ab207ed5a671ed7c2d19c21447552 100644
--- a/media/cast/sender/video_encoder.cc
+++ b/media/cast/sender/video_encoder.cc
@@ -25,8 +25,7 @@ scoped_ptr<VideoEncoder> VideoEncoder::Create(
   // On MacOS or IOS, attempt to use the system VideoToolbox library to
   // perform optimized H.264 encoding.
 #if defined(OS_MACOSX) || defined(OS_IOS)
-  if (!video_config.use_external_encoder &&
-      H264VideoToolboxEncoder::IsSupported(video_config)) {
+  if (H264VideoToolboxEncoder::IsSupported(video_config)) {
     return scoped_ptr<VideoEncoder>(new H264VideoToolboxEncoder(
         cast_environment, video_config, status_change_cb));
   }