ARGBScale to half size adjust address for filtering.

BUG=238
TEST=libyuvTest.ARGBScaleDownBy4_Bilinear
R=dingkai@google.com

Review URL: https://webrtc-codereview.appspot.com/1589004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@711 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 710
+Version: 711
 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 710
+#define LIBYUV_VERSION 711
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/scale_argb.cc

@@ -744,7 +744,11 @@ static void ScaleARGBDown2(int /* src_width */, int /* src_height */,
   assert(dx == 65536 * 2);  // Test scale factor of 2.
   assert((dy & 0x1ffff) == 0);  // Test vertical scale is multiple of 2.
   // Advance to odd row / even column.
-  src_argb += (y >> 16) * src_stride + ((x >> 16) - 1) * 4;
+  if (filtering) {
+    src_argb += (y >> 16) * src_stride + (x >> 16) * 4;
+  } else {
+    src_argb += (y >> 16) * src_stride + ((x >> 16) - 1) * 4;
+  }
   int row_stride = src_stride * (dy >> 16);
   void (*ScaleARGBRowDown2)(const uint8* src_argb, ptrdiff_t src_stride,
                             uint8* dst_argb, int dst_width) =