Add possibility to define data callback to BitmapFetcher

chrome/browser/extensions/webstore_install_helper.cc

Index: chrome/browser/extensions/webstore_install_helper.cc
diff --git a/chrome/browser/extensions/webstore_install_helper.cc b/chrome/browser/extensions/webstore_install_helper.cc
index 948d9954134fe6b38718be0cd34471830942c63a..a2654d00117d695522d1c79b9892c342abede754 100644
--- a/chrome/browser/extensions/webstore_install_helper.cc
+++ b/chrome/browser/extensions/webstore_install_helper.cc
@@ -58,10 +58,11 @@ void WebstoreInstallHelper::Start() {
     CHECK(!icon_fetcher_.get());
     AddRef();  // Balanced in OnFetchComplete().
     icon_fetcher_.reset(new chrome::BitmapFetcher(icon_url_, this));
-    icon_fetcher_->Start(
+    icon_fetcher_->Init(
         context_getter_, std::string(),
         net::URLRequest::CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE,
         net::LOAD_DO_NOT_SAVE_COOKIES | net::LOAD_DO_NOT_SEND_COOKIES);
+    icon_fetcher_->Start();
   }
 
   BrowserThread::PostTask(