Implement support for fallback update check urls in the component updater

components/component_updater/component_updater_service.cc

Index: components/component_updater/component_updater_service.cc
diff --git a/components/component_updater/component_updater_service.cc b/components/component_updater/component_updater_service.cc
index b005a15938c23963a656b0e81c75cda39ebd8c26..aa69cddd1bcde09d019cd54f35fd7c0383dddbfa 100644
--- a/components/component_updater/component_updater_service.cc
+++ b/components/component_updater/component_updater_service.cc
@@ -10,6 +10,7 @@
 
 #include "base/at_exit.h"
 #include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_path.h"
@@ -146,7 +147,8 @@ class CrxUpdateService : public ComponentUpdateService, public OnDemandUpdater {
   // Overrides for OnDemandUpdater.
   virtual Status OnDemandUpdate(const std::string& component_id) OVERRIDE;
 
-  void UpdateCheckComplete(int error,
+  void UpdateCheckComplete(const GURL& original_url,
+                           int error,
                            const std::string& error_message,
                            const UpdateResponse::Results& results);
   void OnUpdateCheckSucceeded(const UpdateResponse::Results& results);
@@ -613,12 +615,12 @@ bool CrxUpdateService::CheckForUpdates() {
   if (items_to_check.empty())
     return false;
 
-  update_checker_ =
-      UpdateChecker::Create(*config_,
-                            base::Bind(&CrxUpdateService::UpdateCheckComplete,
-                                       base::Unretained(this))).Pass();
-  return update_checker_->CheckForUpdates(items_to_check,
-                                          config_->ExtraRequestParams());
+  update_checker_ = UpdateChecker::Create(*config_).Pass();
+  return update_checker_->CheckForUpdates(
+      items_to_check,
+      config_->ExtraRequestParams(),
+      base::Bind(&CrxUpdateService::UpdateCheckComplete,
+                 base::Unretained(this)));
 }
 
 void CrxUpdateService::UpdateComponent(CrxUpdateItem* workitem) {
@@ -661,10 +663,12 @@ void CrxUpdateService::UpdateComponent(CrxUpdateItem* workitem) {
 }
 
 void CrxUpdateService::UpdateCheckComplete(
+    const GURL& original_url,
     int error,
     const std::string& error_message,
     const UpdateResponse::Results& results) {
   DCHECK(thread_checker_.CalledOnValidThread());
+  VLOG(1) << "Update check completed from: " << original_url.spec();
   update_checker_.reset();
   if (!error)
     OnUpdateCheckSucceeded(results);