Fix race conditions in ImageDecoder.

chrome/browser/chromeos/extensions/wallpaper_function_base.cc

 // Copyright 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/extensions/wallpaper_function_base.h"
 
 #include "base/synchronization/cancellation_flag.h"
 #include "chrome/browser/image_decoder.h"
 #include "chrome/grit/generated_resources.h"
 #include "chromeos/login/login_state.h"
@@ skipping 27 matching lines @@
   // Default to use CENTER layout.
   return wallpaper::WALLPAPER_LAYOUT_CENTER;
 }
 
 }  // namespace wallpaper_api_util
 
 class WallpaperFunctionBase::UnsafeWallpaperDecoder
     : public ImageDecoder::ImageRequest {
  public:
   explicit UnsafeWallpaperDecoder(scoped_refptr<WallpaperFunctionBase> function)
-      : ImageRequest(
-            BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI)),
-        function_(function) {}
+      : function_(function) {}
 
   void Start(const std::vector<char>& image_data) {
     DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
     // This function can only be called after user login. It is fine to use
     // unsafe image decoder here. Before user login, a robust jpeg decoder will
     // be used.
     CHECK(chromeos::LoginState::Get()->IsUserLoggedIn());
     std::string image_data_str(image_data.begin(), image_data.end());
     ImageDecoder::StartWithOptions(this, image_data_str,
@@ skipping 54 matching lines @@
   unsafe_wallpaper_decoder_ = NULL;
   SetError(wallpaper_api_util::kCancelWallpaperMessage);
   SendResponse(false);
 }
 
 void WallpaperFunctionBase::OnFailure(const std::string& error) {
   unsafe_wallpaper_decoder_ = NULL;
   SetError(error);
   SendResponse(false);
 }