Fix valgrind warnings in YUV scaling code.

media/base/yuv_convert.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This webpage shows layout of YV12 and other YUV formats
 // http://www.fourcc.org/yuv.php
 // The actual conversion is best described here
 // http://en.wikipedia.org/wiki/YUV
 // An article on optimizing YUV conversion using tables instead of multiplies
 // http://lestourtereaux.free.fr/papers/data/yuvrgb.pdf
 //
 // YV12 is a full plane of Y and a half height, half width chroma planes
 // YV16 is a full plane of Y and a full height, half width chroma planes
 //
 // ARGB pixel format is output, which on little endian is stored as BGRA.
 // The alpha is set to 255, allowing the application to use RGBA or RGB32.
 
 #include "media/base/yuv_convert.h"
 
 #include "base/cpu.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "build/build_config.h"
 #include "media/base/simd/convert_rgb_to_yuv.h"
 #include "media/base/simd/convert_yuv_to_rgb.h"
 #include "media/base/simd/filter_yuv.h"
 
 #if defined(ARCH_CPU_X86_FAMILY)
 #if defined(COMPILER_MSVC)
 #include <intrin.h>
 #else
 #include <mmintrin.h>
@@ skipping 404 matching lines @@
 
   // Intermediate buffer for vertical interpolation.
   // 4096 bytes allows 3 buffers to fit in 12k, which fits in a 16K L1 cache,
   // and is bigger than most users will generally need.
   // The buffer is 16-byte aligned and padded with 16 extra bytes; some of the
   // FilterYUVRowProcs have alignment requirements, and the SSE version can
   // write up to 16 bytes past the end of the buffer.
   const int kFilterBufferSize = 4096;
   const bool kAvoidUsingOptimizedFilter = source_width > kFilterBufferSize;
   uint8 yuv_temp[16 + kFilterBufferSize * 3 + 16];
+  // memset() yuv_temp to 0 to avoid bogus warnings when running on Valgrind.
+  if (RunningOnValgrind())
+    memset(yuv_temp, 0, sizeof(yuv_temp));
   uint8* y_temp = reinterpret_cast<uint8*>(
       reinterpret_cast<uintptr_t>(yuv_temp + 15) & ~15);
   uint8* u_temp = y_temp + kFilterBufferSize;
   uint8* v_temp = u_temp + kFilterBufferSize;
 
   // Move to the top-left pixel of output.
   rgb_buf += dest_rect_top * rgb_pitch;
   rgb_buf += dest_rect_left * 4;
 
   // For each destination row perform interpolation and color space
@@ skipping 189 matching lines @@
                                width,
                                height,
                                ystride,
                                uvstride,
                                astride,
                                rgbstride,
                                yuv_type);
 }
 
 }  // namespace media