Fixes use-of-uninitialized-value MSan error in image_skia_unittest

ui/gfx/image/image_skia_rep.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.
 
 #include "ui/gfx/image/image_skia_rep.h"
 
 #include "base/logging.h"
 
 namespace gfx {
 
 ImageSkiaRep::ImageSkiaRep() : scale_(0.0f) {
 }
 
 ImageSkiaRep::~ImageSkiaRep() {
 }
 
 ImageSkiaRep::ImageSkiaRep(const gfx::Size& size, float scale) : scale_(scale) {
   bitmap_.setConfig(SkBitmap::kARGB_8888_Config,
                     static_cast<int>(size.width() * this->scale()),
                     static_cast<int>(size.height() * this->scale()));
   bitmap_.allocPixels();
+  bitmap_.eraseColor(SK_ColorRED);
 }
 
 ImageSkiaRep::ImageSkiaRep(const SkBitmap& src, float scale)
     : bitmap_(src),
       scale_(scale) {
 }
 
 int ImageSkiaRep::GetWidth() const {
   return static_cast<int>(bitmap_.width() / scale());
 }
 
 int ImageSkiaRep::GetHeight() const {
   return static_cast<int>(bitmap_.height() / scale());
 }
 
 void ImageSkiaRep::SetScaled() {
   DCHECK_EQ(0.0f, scale_);
   if (scale_ == 0.0f)
     scale_ = 1.0f;
 }
 
 }  // namespace gfx