media: Add support for playback of VP8 Alpha video streams

media/base/yuv_convert.h

Index: media/base/yuv_convert.h
diff --git a/media/base/yuv_convert.h b/media/base/yuv_convert.h
index 30c07abf683831759307d60dfd2322060b94e73b..0e5319372e88105398c4c1d9156b3c033ed3c617 100644
--- a/media/base/yuv_convert.h
+++ b/media/base/yuv_convert.h
@@ -60,6 +60,21 @@ void ConvertYUVToRGB32(const uint8* yplane,
                        int rgbstride,
                        YUVType yuv_type);
 
+// Convert a frame of YUVA to 32 bit ARGB.
+// Pass in YV12A
+void ConvertYUVAToARGB(const uint8* yplane,
+                       const uint8* uplane,
+                       const uint8* vplane,
+                       const uint8* aplane,
+                       uint8* rgbframe,
+                       int width,
+                       int height,
+                       int ystride,
+                       int uvstride,
+                       int astride,
+                       int rgbstride,
+                       YUVType yuv_type);
+
 // Scale a frame of YUV to 32 bit ARGB.
 // Supports rotation and mirroring.
 void ScaleYUVToRGB32(const uint8* yplane,