Address races in UserImageManagerImpl

chrome/browser/chromeos/login/user_image_loader.cc

 // Copyright (c) 2013 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 "chrome/browser/chromeos/login/user_image_loader.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
@@ skipping 48 matching lines @@
                                         this,
                                         base::Passed(&data),
                                         ImageInfo(size, loaded_cb)));
 }
 
 void UserImageLoader::ReadAndDecodeImage(const std::string& filepath,
                                          const ImageInfo& image_info) {
   DCHECK(background_task_runner_->RunsTasksOnCurrentThread());
 
   scoped_ptr<std::string> data(new std::string);
-  base::ReadFileToString(base::FilePath(filepath), data.get());
+  const bool success =
+      base::ReadFileToString(base::FilePath(filepath), data.get());
+  DCHECK(success);
 
   DecodeImage(data.Pass(), image_info);
 }
 
 void UserImageLoader::DecodeImage(const scoped_ptr<std::string> data,
                                   const ImageInfo& image_info) {
   DCHECK(background_task_runner_->RunsTasksOnCurrentThread());
 
   scoped_refptr<ImageDecoder> image_decoder =
       new ImageDecoder(this, *data, image_codec_);
@@ skipping 56 matching lines @@
     return;
   }
   const LoadedCallback loaded_cb = it->second.loaded_cb;
   image_info_map_.erase(it);
 
   foreground_task_runner_->PostTask(FROM_HERE,
                                     base::Bind(loaded_cb, UserImage()));
 }
 
 }  // namespace chromeos