Implements RGB to YV12 conversion in YASM.

media/base/yuv_convert.cc

Index: media/base/yuv_convert.cc
===================================================================
--- media/base/yuv_convert.cc	(revision 99884)
+++ media/base/yuv_convert.cc	(working copy)
@@ -19,6 +19,7 @@
 
 #include "build/build_config.h"
 #include "media/base/cpu_features.h"
+#include "media/base/simd/convert_rgb_to_yuv.h"
 #include "media/base/yuv_convert_internal.h"
 #include "media/base/yuv_row.h"
 
@@ -369,8 +370,10 @@
     // TODO(hclam): Implement a NEON version.
     convert_proc = &ConvertRGB32ToYUV_C;
 #else
-    // For x86 processors, check if SSE2 is supported.
-    if (hasSSE2())
+    // For x86 processors, check if SSSE3 (or SSE2) is supported.
+    if (hasSSSE3())
+      convert_proc = &ConvertRGB32ToYUV_SSSE3;
+    else if (hasSSE2())
       convert_proc = &ConvertRGB32ToYUV_SSE2;
     else
       convert_proc = &ConvertRGB32ToYUV_C;
@@ -390,8 +393,21 @@
                        int rgbstride,
                        int ystride,
                        int uvstride) {
+#if defined(ARCH_CPU_ARM_FAMILY)
   ConvertRGB24ToYUV_C(rgbframe, yplane, uplane, vplane, width, height,
                       rgbstride, ystride, uvstride);
+#else
+  static void (*convert_proc)(const uint8*, uint8*, uint8*, uint8*,
+                              int, int, int, int, int) = NULL;
+  if (!convert_proc) {
+    if (hasSSSE3())
+      convert_proc = &ConvertRGB24ToYUV_SSSE3;
+    else
+      convert_proc = &ConvertRGB24ToYUV_C;
+  }
+  convert_proc(rgbframe, yplane, uplane, vplane, width, height,
+               rgbstride, ystride, uvstride);
+#endif
 }
 
 void ConvertYUY2ToYUV(const uint8* src,