port YUV luma accuracy to posix

BUG=324
TESTED=try bots
R=harryjin@google.com

Review URL: https://webrtc-codereview.appspot.com/33049004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1236 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1232
+Version: 1236
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1232
+#define LIBYUV_VERSION 1236
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/row_win.cc

@@ -2288,9 +2288,7 @@ void I422ToRGBARow_SSSE3(const uint8* y_buf,
 
 #endif  // HAS_I422TOARGBROW_SSSE3
 
-#define YG 19071 /* round(1.164 * 64 * 256) */
-#define YGB 1192  /* round(1.164 * 64 * 16) */
-
+// TODO(fbarchard): Remove shift by 6.
 #ifdef HAS_YTOARGBROW_SSE2
 __declspec(naked) __declspec(align(16))
 void YToARGBRow_SSE2(const uint8* y_buf,