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 4b33b46b2755377bf87081b465631b786243cde6..798ed5e1dae9dbe0080a72e4fce08b0c6a438958 100644
--- a/chrome/browser/extensions/webstore_install_helper.cc
+++ b/chrome/browser/extensions/webstore_install_helper.cc
@@ -57,10 +57,11 @@ 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(