Warning fixes for implicite casts that vs2012 complains about with higher warning levels

BUG=302
TESTED=hammer build
R=tpsiaki@google.com

Review URL: https://webrtc-codereview.appspot.com/6559004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@948 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 947
+Version: 948
 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 947
+#define LIBYUV_VERSION 948
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/scale_argb.cc

@@ -178,7 +178,7 @@ static void ScaleARGBBilinearDown(int src_width, int src_height,
   xr = (xr >> 16) + 1;  // Right most pixel used.
   int clip_src_width = (((xr - xl) + 1 + 3) & ~3) * 4;  // Width aligned to 4.
   src_argb += xl * 4;
-  x -= (xl << 16);
+  x -= static_cast<int>(xl << 16);
   void (*InterpolateRow)(uint8* dst_argb, const uint8* src_argb,
       ptrdiff_t src_stride, int dst_width, int source_y_fraction) =
       InterpolateRow_C;

source/scale_common.cc

@@ -204,8 +204,8 @@ void ScaleColsUp2_C(uint8* dst_ptr, const uint8* src_ptr,
 }
 
 // (1-f)a + fb can be replaced with a + f(b-a)
-#define BLENDER(a, b, f) (static_cast<int>(a) + \
-    ((f) * (static_cast<int>(b) - static_cast<int>(a)) >> 16))
+#define BLENDER(a, b, f) static_cast<uint8>(static_cast<int>(a) + \
+    (static_cast<int>(f) * (static_cast<int>(b) - static_cast<int>(a)) >> 16))
 
 void ScaleFilterCols_C(uint8* dst_ptr, const uint8* src_ptr,
                        int dst_width, int x, int dx) {