media: Add support for playback of VP8 Alpha video streams

content/browser/renderer_host/media/video_capture_controller.cc

Index: content/browser/renderer_host/media/video_capture_controller.cc
diff --git a/content/browser/renderer_host/media/video_capture_controller.cc b/content/browser/renderer_host/media/video_capture_controller.cc
index 25d41a54d2a433c5f2d29ac46e757c2d38a9b301..b82b7969ca7b13a82c258f36b5cdabcbdd30fc39 100644
--- a/content/browser/renderer_host/media/video_capture_controller.cc
+++ b/content/browser/renderer_host/media/video_capture_controller.cc
@@ -398,6 +398,7 @@ void VideoCaptureController::OnIncomingCapturedVideoFrame(
   const int kYPlane = media::VideoFrame::kYPlane;
   const int kUPlane = media::VideoFrame::kUPlane;
   const int kVPlane = media::VideoFrame::kVPlane;
+  const int kAPlane = media::VideoFrame::kAPlane;
   const int kRGBPlane = media::VideoFrame::kRGBPlane;
 
   // Do color conversion from the camera format to I420.
@@ -430,6 +431,26 @@ void VideoCaptureController::OnIncomingCapturedVideoFrame(
                         target);
       break;
     }
+    case media::VideoFrame::YV12A: {
+      DCHECK(!chopped_width_ && !chopped_height_);
+      media::CopyYPlane(frame->data(kYPlane),
+                        frame->stride(kYPlane),
+                        frame->rows(kYPlane),
+                        target);
+      media::CopyUPlane(frame->data(kUPlane),
+                        frame->stride(kUPlane),
+                        frame->rows(kUPlane),
+                        target);
+      media::CopyVPlane(frame->data(kVPlane),
+                        frame->stride(kVPlane),
+                        frame->rows(kVPlane),
+                        target);
+      media::CopyAPlane(frame->data(kAPlane),
+                        frame->stride(kAPlane),
+                        frame->rows(kAPlane),
+                        target);
+      break;
+    }
     case media::VideoFrame::RGB32: {
       media::ConvertRGB32ToYUV(frame->data(kRGBPlane),
                                target->data(kYPlane),