Reland: Tie kWebRtcH264WithOpenH264FFmpeg and kEnableWebRtcHWH264Encoding flags on Mac

media/gpu/vt_video_encode_accelerator_mac.cc

Index: media/gpu/vt_video_encode_accelerator_mac.cc
diff --git a/media/gpu/vt_video_encode_accelerator_mac.cc b/media/gpu/vt_video_encode_accelerator_mac.cc
index f9fadaf26652e3363508d7f680e294cf4fec93d7..dffc39ddaf463fc1e5a6f54635d5d3a0340a04ea 100644
--- a/media/gpu/vt_video_encode_accelerator_mac.cc
+++ b/media/gpu/vt_video_encode_accelerator_mac.cc
@@ -6,6 +6,7 @@
 
 #include <memory>
 
+#include "base/mac/mac_util.h"
 #include "base/thread_task_runner_handle.h"
 #include "media/base/mac/coremedia_glue.h"
 #include "media/base/mac/corevideo_glue.h"
@@ -90,6 +91,11 @@ VTVideoEncodeAccelerator::GetSupportedProfiles() {
     DLOG(ERROR) << "Failed creating VideoToolbox glue.";
     return profiles;
   }
+  if (!base::mac::IsOSMavericksOrLater()) {
+    DLOG(ERROR) << "VideoToolbox hardware encoder is supported on Mac OS 10.9 "
+                   "and later.";
+    return profiles;
+  }
   const bool rv = CreateCompressionSession(
       media::video_toolbox::DictionaryWithKeysAndValues(nullptr, nullptr, 0),
       gfx::Size(kDefaultResolutionWidth, kDefaultResolutionHeight), true);
@@ -138,6 +144,11 @@ bool VTVideoEncodeAccelerator::Initialize(
     DLOG(ERROR) << "Failed creating VideoToolbox glue.";
     return false;
   }
+  if (!base::mac::IsOSMavericksOrLater()) {
+    DLOG(ERROR) << "VideoToolbox hardware encoder is supported on Mac OS 10.9 "
+                   "and later.";
+    return false;
+  }
 
   client_ptr_factory_.reset(new base::WeakPtrFactory<Client>(client));
   client_ = client_ptr_factory_->GetWeakPtr();