Add native-handle support for single VP8 streams.

webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc

Index: webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc
diff --git a/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc b/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc
index 1b59be35368b461d87c7065bf7957e6e752f4f78..9ac2efabe624dc395d6d6ed5e351cd8e7d481d26 100644
--- a/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc
+++ b/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc
@@ -15,6 +15,7 @@
 // NOTE(ajm): Path provided by gyp.
 #include "libyuv/scale.h"  // NOLINT
 
+#include "webrtc/base/checks.h"
 #include "webrtc/common.h"
 #include "webrtc/modules/video_coding/codecs/vp8/screenshare_layers.h"
 
@@ -497,4 +498,13 @@ int SimulcastEncoderAdapter::GetTargetFramerate() {
   return streaminfos_[0].encoder->GetTargetFramerate();
 }
 
+bool SimulcastEncoderAdapter::SupportsNativeHandle() const {
+  // We should not be calling this method before streaminfos_ are configured.
+  RTC_DCHECK(!streaminfos_.empty());
+  // TODO(pbos): Support textures when using more than one encoder.
+  if (streaminfos_.size() != 1)
+    return false;
+  return streaminfos_[0].encoder->SupportsNativeHandle();
+}
+
 }  // namespace webrtc