SystemInfo API: Fix SystemInfoEventRouter initialization code.

chrome/browser/extensions/api/system_info/system_info_api.cc

Index: chrome/browser/extensions/api/system_info/system_info_api.cc
===================================================================
--- chrome/browser/extensions/api/system_info/system_info_api.cc	(revision 245000)
+++ chrome/browser/extensions/api/system_info/system_info_api.cc	(working copy)
@@ -68,7 +68,7 @@
   // Called from any thread to dispatch the systemInfo event to all extension
   // processes cross multiple profiles.
   void DispatchEvent(const std::string& event_name,
-      scoped_ptr<base::ListValue> args);
+                     scoped_ptr<base::ListValue> args);
 
   // Called to dispatch the systemInfo.display.onDisplayChanged event.
   void OnDisplayChanged();
@@ -89,7 +89,6 @@
 
 SystemInfoEventRouter::SystemInfoEventRouter() {
   StorageMonitor::GetInstance()->AddObserver(this);
-  StorageMonitor::GetInstance()->EnsureInitialized(base::Closure());
 }
 
 SystemInfoEventRouter::~SystemInfoEventRouter() {
@@ -112,8 +111,7 @@
   }
 }
 
-void SystemInfoEventRouter::RemoveEventListener(
-    const std::string& event_name) {
+void SystemInfoEventRouter::RemoveEventListener(const std::string& event_name) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   std::multiset<std::string>::iterator it =
@@ -173,6 +171,16 @@
       BroadcastEventToRenderers(event_name, args.Pass(), GURL());
 }
 

[Haojian Wu, 2014/01/16 06:53:27]

Some performance concerns: everytime we add an systemInfo event, we will invoke
StorageMonitor::EnsureInitialized to make sure StorageMonitor is constructed.
The type of systemInfo event is including display, so when we add display event,
the checking is unnecessay.

[Lei Zhang, 2014/01/16 23:24:11]

See patch set 2.

+void AddEventListener(const std::string& event_name) {
+  DCHECK(StorageMonitor::GetInstance()->IsInitialized());
+  SystemInfoEventRouter::GetInstance()->AddEventListener(event_name);
+}
+
+void RemoveEventListener(const std::string& event_name) {
+  DCHECK(StorageMonitor::GetInstance()->IsInitialized());
+  SystemInfoEventRouter::GetInstance()->RemoveEventListener(event_name);
+}
+
 }  // namespace
 
 static base::LazyInstance<ProfileKeyedAPIFactory<SystemInfoAPI> >
@@ -200,11 +208,13 @@
 }
 
 void SystemInfoAPI::OnListenerAdded(const EventListenerInfo& details) {
-  SystemInfoEventRouter::GetInstance()->AddEventListener(details.event_name);
+  StorageMonitor::GetInstance()->EnsureInitialized(
+      base::Bind(&AddEventListener, details.event_name));
 }
 
 void SystemInfoAPI::OnListenerRemoved(const EventListenerInfo& details) {
-  SystemInfoEventRouter::GetInstance()->RemoveEventListener(details.event_name);
+  StorageMonitor::GetInstance()->EnsureInitialized(
+      base::Bind(&RemoveEventListener, details.event_name));
 }
 
 }  // namespace extensions