Make image_decoder a Leaky LazyInstance

chrome/browser/bitmap_fetcher/bitmap_fetcher.cc

 // Copyright 2014 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/bitmap_fetcher/bitmap_fetcher.h"
 
 #include "content/public/browser/browser_thread.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "net/url_request/url_request_status.h"
 
 namespace chrome {
 
 BitmapFetcher::BitmapFetcher(const GURL& url, BitmapFetcherDelegate* delegate)
-    : url_(url), delegate_(delegate) {
+    : ImageRequest(content::BrowserThread::GetMessageLoopProxyForThread(
+          content::BrowserThread::UI)),
+      url_(url),
+      delegate_(delegate) {
 }
 
 BitmapFetcher::~BitmapFetcher() {
 }
 
 void BitmapFetcher::Start(net::URLRequestContextGetter* request_context,
                           const std::string& referrer,
                           net::URLRequest::ReferrerPolicy referrer_policy,
                           int load_flags) {
   if (url_fetcher_ != NULL)
@@ skipping 12 matching lines @@
 void BitmapFetcher::OnURLFetchComplete(const net::URLFetcher* source) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
   if (source->GetStatus().status() != net::URLRequestStatus::SUCCESS) {
     ReportFailure();
     return;
   }
 
   std::string image_data;
   source->GetResponseAsString(&image_data);
-  image_decoder_ =
-      new ImageDecoder(this, image_data, ImageDecoder::DEFAULT_CODEC);
 
   // Call start to begin decoding.  The ImageDecoder will call OnImageDecoded
   // with the data when it is done.
-  scoped_refptr<base::MessageLoopProxy> task_runner =
-      content::BrowserThread::GetMessageLoopProxyForThread(
-          content::BrowserThread::UI);
-  image_decoder_->Start(task_runner);
+  ImageDecoder::Start(this, image_data);
 }
 
 void BitmapFetcher::OnURLFetchDownloadProgress(const net::URLFetcher* source,
                                                int64 current,
                                                int64 total) {
   // Do nothing here.
 }
 
-// Methods inherited from ImageDecoder::Delegate.
+// Methods inherited from ImageDecoder::ImageRequest.
 
-void BitmapFetcher::OnImageDecoded(const ImageDecoder* decoder,
-                                   const SkBitmap& decoded_image) {
+void BitmapFetcher::OnImageDecoded(const SkBitmap& decoded_image) {
   // Report success.
   delegate_->OnFetchComplete(url_, &decoded_image);
 }
 
-void BitmapFetcher::OnDecodeImageFailed(const ImageDecoder* decoder) {
+void BitmapFetcher::OnDecodeImageFailed() {
   ReportFailure();
 }
 
 void BitmapFetcher::ReportFailure() {
   delegate_->OnFetchComplete(url_, NULL);
 }
 
 }  // namespace chrome