Fix race conditions in ImageDecoder.

chrome/browser/ui/app_list/search/common/url_icon_source.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/ui/app_list/search/common/url_icon_source.h"
 
 #include <string>
 
 #include "content/public/browser/browser_thread.h"
 #include "net/base/load_flags.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_status.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/image/image_skia_operations.h"
 
 using content::BrowserThread;
 
 namespace app_list {
 
 UrlIconSource::UrlIconSource(const IconLoadedCallback& icon_loaded_callback,
                              net::URLRequestContextGetter* context_getter,
                              const GURL& icon_url,
                              int icon_size,
                              int default_icon_resource_id)
-    : ImageRequest(
-          BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI)),
-      icon_loaded_callback_(icon_loaded_callback),
+    : icon_loaded_callback_(icon_loaded_callback),
       context_getter_(context_getter),
       icon_url_(icon_url),
       icon_size_(icon_size),
       default_icon_resource_id_(default_icon_resource_id),
       icon_fetch_attempted_(false) {
   DCHECK(!icon_loaded_callback_.is_null());
 }
 
 UrlIconSource::~UrlIconSource() {
 }
@@ skipping 43 matching lines @@
       gfx::Size(icon_size_, icon_size_));
 
   icon_loaded_callback_.Run();
 }
 
 void UrlIconSource::OnDecodeImageFailed() {
   // Failed to decode image. Do nothing and just use the default icon.
 }
 
 }  // namespace app_list