media: Add support for playback of VP8 Alpha video streams

media/base/simd/convert_yuva_to_argb_mmx.asm

Index: media/base/simd/convert_yuva_to_argb_mmx.asm
diff --git a/media/base/simd/convert_yuv_to_rgb_mmx.asm b/media/base/simd/convert_yuva_to_argb_mmx.asm
similarity index 73%
copy from media/base/simd/convert_yuv_to_rgb_mmx.asm
copy to media/base/simd/convert_yuva_to_argb_mmx.asm
index 39a4f75697dc691dbad0c22fbd1c10c225dc96de..b39315dc461bb61e003f467c13f3925b9a8b3368 100644
--- a/media/base/simd/convert_yuv_to_rgb_mmx.asm
+++ b/media/base/simd/convert_yuva_to_argb_mmx.asm
@@ -13,10 +13,11 @@
 ; Use movq to save the output.
 %define MOVQ movq
 
-; extern "C" void ConvertYUVToRGB32Row_MMX(const uint8* y_buf,
+; extern "C" void ConvertYUVAToARGBRow_MMX(const uint8* y_buf,
 ;                                          const uint8* u_buf,
 ;                                          const uint8* v_buf,
+;                                          const uint8* a_buf,
 ;                                          uint8* rgb_buf,
 ;                                          ptrdiff_t width);
-%define SYMBOL ConvertYUVToRGB32Row_MMX
-%include "convert_yuv_to_rgb_mmx.inc"
+%define SYMBOL ConvertYUVAToARGBRow_MMX
+%include "convert_yuva_to_argb_mmx.inc"