Refactor VideoDestinationHandler to implement MediaStreamVideoSource.

content/renderer/media/rtc_media_constraints.cc

Index: content/renderer/media/rtc_media_constraints.cc
diff --git a/content/renderer/media/rtc_media_constraints.cc b/content/renderer/media/rtc_media_constraints.cc
index a476be3a38aab6274428bad0358db391cec88748..7f8b79dc136dadb26c3150abbe83f422a1c52559 100644
--- a/content/renderer/media/rtc_media_constraints.cc
+++ b/content/renderer/media/rtc_media_constraints.cc
@@ -8,6 +8,7 @@
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "content/common/media/media_stream_options.h"
+#include "content/renderer/media/media_stream_video_source.h"
 #include "third_party/WebKit/public/platform/WebMediaConstraints.h"
 #include "third_party/WebKit/public/platform/WebCString.h"
 #include "third_party/WebKit/public/platform/WebString.h"
@@ -33,6 +34,10 @@ void GetNativeMediaConstraints(
     if (new_constraint.key == kMediaStreamSourceInfoId)
       continue;
 
+    // Ignore constraints that are handled by Chrome in MediaStreamVideoSource.
+    if (MediaStreamVideoSource::IsConstraintSupported(new_constraint.key))
+      continue;
+
     DVLOG(3) << "MediaStreamConstraints:" << new_constraint.key
              << " : " <<  new_constraint.value;
     native_constraints->push_back(new_constraint);