Add possibility to define data callback to BitmapFetcher

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) {
 }
 
 BitmapFetcher::~BitmapFetcher() {
 }
 
-void BitmapFetcher::Start(net::URLRequestContextGetter* request_context,
-                          const std::string& referrer,
-                          net::URLRequest::ReferrerPolicy referrer_policy,
-                          int load_flags) {
+void BitmapFetcher::Init(net::URLRequestContextGetter* request_context,
+                         const std::string& referrer,
+                         net::URLRequest::ReferrerPolicy referrer_policy,
+                         int load_flags) {
   if (url_fetcher_ != NULL)

[sky, 2015/06/08 15:05:29]

In general we DCHECK people calling Init multiple times.

     return;
 
   url_fetcher_ = net::URLFetcher::Create(url_, net::URLFetcher::GET, this);
   url_fetcher_->SetRequestContext(request_context);
   url_fetcher_->SetReferrer(referrer);
   url_fetcher_->SetReferrerPolicy(referrer_policy);
   url_fetcher_->SetLoadFlags(load_flags);
+}
+
+void BitmapFetcher::Start() {
   url_fetcher_->Start();

[sky, 2015/06/08 15:05:29]

The old code early outed if url_fecher_ was already set. Why is that not
necessary anymore?

 }
 
 // Methods inherited from URLFetcherDelegate.
 
 void BitmapFetcher::OnURLFetchComplete(const net::URLFetcher* source) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   if (source->GetStatus().status() != net::URLRequestStatus::SUCCESS) {
     ReportFailure();
     return;
@@ skipping 22 matching lines @@
 
 void BitmapFetcher::OnDecodeImageFailed() {
   ReportFailure();
 }
 
 void BitmapFetcher::ReportFailure() {
   delegate_->OnFetchComplete(url_, NULL);
 }
 
 }  // namespace chrome