Hold URLRequestContextGetter by scoped_refptr in Drive related code.

chrome/browser/drive/gdata_wapi_service.cc

Index: chrome/browser/drive/gdata_wapi_service.cc
diff --git a/chrome/browser/drive/gdata_wapi_service.cc b/chrome/browser/drive/gdata_wapi_service.cc
index c1fb7be9c480bc84a516a6ad3a9ee484fc3501ef..efe3bea999b2a42e50c3b4d68b82c719c607e86c 100644
--- a/chrome/browser/drive/gdata_wapi_service.cc
+++ b/chrome/browser/drive/gdata_wapi_service.cc
@@ -19,6 +19,7 @@
 #include "chrome/browser/google_apis/gdata_wapi_url_generator.h"
 #include "chrome/browser/google_apis/request_sender.h"
 #include "content/public/browser/browser_thread.h"
+#include "net/url_request/url_request_context_getter.h"
 
 using content::BrowserThread;
 using google_apis::AboutResource;
@@ -160,9 +161,9 @@ void GDataWapiService::Initialize(const std::string& account_id) {
   sender_.reset(new RequestSender(
       new AuthService(oauth2_token_service_,
                       account_id,
-                      url_request_context_getter_,
+                      url_request_context_getter_.get(),
                       scopes),
-      url_request_context_getter_,
+      url_request_context_getter_.get(),
       blocking_task_runner_.get(),
       custom_user_agent_));