Cleanup: Simplify system_info_api.cc.

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

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/api/system_info/system_info_api.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
@@ skipping 19 matching lines @@
 namespace extensions {
 
 using api::system_storage::StorageUnitInfo;
 using content::BrowserThread;
 
 namespace system_display = api::system_display;
 namespace system_storage = api::system_storage;
 
 namespace {
 
+#if defined(USE_ASH)
 bool IsDisplayChangedEvent(const std::string& event_name) {
   return event_name == system_display::OnDisplayChanged::kEventName;
 }
+#endif
 
 // Event router for systemInfo API. It is a singleton instance shared by
 // multiple profiles.
 class SystemInfoEventRouter : public gfx::DisplayObserver,
                               public RemovableStorageObserver {
  public:
   static SystemInfoEventRouter* GetInstance();
 
   SystemInfoEventRouter();
   virtual ~SystemInfoEventRouter();
 
   // Add/remove event listener for the |event_name| event.
   void AddEventListener(const std::string& event_name);
   void RemoveEventListener(const std::string& event_name);
 
  private:
   // gfx::DisplayObserver:
   virtual void OnDisplayBoundsChanged(const gfx::Display& display) OVERRIDE;
   virtual void OnDisplayAdded(const gfx::Display& new_display) OVERRIDE;
   virtual void OnDisplayRemoved(const gfx::Display& old_display) OVERRIDE;
 
   // RemovableStorageObserver implementation.
   virtual void OnRemovableStorageAttached(const StorageInfo& info) OVERRIDE;
   virtual void OnRemovableStorageDetached(const StorageInfo& info) OVERRIDE;
 
   // 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();
 
   // Used to record the event names being watched.
   std::multiset<std::string> watching_event_set_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemInfoEventRouter);
 };
 
 static base::LazyInstance<SystemInfoEventRouter>::Leaky
-  g_system_info_event_router = LAZY_INSTANCE_INITIALIZER;
+    g_system_info_event_router = LAZY_INSTANCE_INITIALIZER;
 
 // static
 SystemInfoEventRouter* SystemInfoEventRouter::GetInstance() {
   return g_system_info_event_router.Pointer();
 }
 
 SystemInfoEventRouter::SystemInfoEventRouter() {
   StorageMonitor::GetInstance()->AddObserver(this);
   StorageMonitor::GetInstance()->EnsureInitialized(base::Closure());
 }
 
 SystemInfoEventRouter::~SystemInfoEventRouter() {
   if (StorageMonitor* storage_monitor = StorageMonitor::GetInstance())
     storage_monitor->RemoveObserver(this);
 }
 
 void SystemInfoEventRouter::AddEventListener(const std::string& event_name) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   watching_event_set_.insert(event_name);
   if (watching_event_set_.count(event_name) > 1)
     return;
 
   // For systemInfo.display event.
-  if (IsDisplayChangedEvent(event_name)) {
 #if defined(USE_ASH)
+  if (IsDisplayChangedEvent(event_name))
     ash::Shell::GetScreen()->AddObserver(this);
 #endif
-  }
 }
 
 void SystemInfoEventRouter::RemoveEventListener(
     const std::string& event_name) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   std::multiset<std::string>::iterator it =
       watching_event_set_.find(event_name);
-  if (it != watching_event_set_.end())
+  if (it != watching_event_set_.end()) {
     watching_event_set_.erase(it);
+    if (watching_event_set_.count(event_name) > 0)
+      return;
+  }
 
-  if (watching_event_set_.count(event_name) > 0)
-    return;
-
-  if (IsDisplayChangedEvent(event_name)) {
 #if defined(USE_ASH)
+  if (IsDisplayChangedEvent(event_name))
     ash::Shell::GetScreen()->RemoveObserver(this);
 #endif
-  }
 }
 
 void SystemInfoEventRouter::OnRemovableStorageAttached(
     const StorageInfo& info) {
   StorageUnitInfo unit;
   systeminfo::BuildStorageUnitInfo(info, &unit);
   scoped_ptr<base::ListValue> args(new base::ListValue);
   args->Append(unit.ToValue().release());
   DispatchEvent(system_storage::OnAttached::kEventName, args.Pass());
 }
 
 void SystemInfoEventRouter::OnRemovableStorageDetached(
     const StorageInfo& info) {
   scoped_ptr<base::ListValue> args(new base::ListValue);
-  args->Append(new base::StringValue(StorageMonitor::GetInstance()->
-                   GetTransientIdForDeviceId(info.device_id())));
+  std::string transient_id =
+      StorageMonitor::GetInstance()->GetTransientIdForDeviceId(
+          info.device_id());
+  args->AppendString(transient_id);
 
   DispatchEvent(system_storage::OnDetached::kEventName, args.Pass());
 }
 
 void SystemInfoEventRouter::OnDisplayBoundsChanged(
     const gfx::Display& display) {
   OnDisplayChanged();
 }
 
 void SystemInfoEventRouter::OnDisplayAdded(const gfx::Display& new_display) {
@@ skipping 15 matching lines @@
       BroadcastEventToRenderers(event_name, args.Pass(), GURL());
 }
 
 }  // namespace
 
 static base::LazyInstance<ProfileKeyedAPIFactory<SystemInfoAPI> >
     g_factory = LAZY_INSTANCE_INITIALIZER;
 
 // static
 ProfileKeyedAPIFactory<SystemInfoAPI>* SystemInfoAPI::GetFactoryInstance() {
-  return &g_factory.Get();
+  return g_factory.Pointer();
 }
 
 SystemInfoAPI::SystemInfoAPI(Profile* profile) : profile_(profile) {
-  ExtensionSystem::Get(profile_)->event_router()->RegisterObserver(
-      this, system_storage::OnAttached::kEventName);
-  ExtensionSystem::Get(profile_)->event_router()->RegisterObserver(
-      this, system_storage::OnDetached::kEventName);
-  ExtensionSystem::Get(profile_)->event_router()->RegisterObserver(
-      this, system_display::OnDisplayChanged::kEventName);
+  EventRouter* router = ExtensionSystem::Get(profile_)->event_router();
+  router->RegisterObserver(this, system_storage::OnAttached::kEventName);
+  router->RegisterObserver(this, system_storage::OnDetached::kEventName);
+  router->RegisterObserver(this, system_display::OnDisplayChanged::kEventName);
 }
 
 SystemInfoAPI::~SystemInfoAPI() {
 }
 
 void SystemInfoAPI::Shutdown() {
   ExtensionSystem::Get(profile_)->event_router()->UnregisterObserver(this);
 }
 
 void SystemInfoAPI::OnListenerAdded(const EventListenerInfo& details) {
   SystemInfoEventRouter::GetInstance()->AddEventListener(details.event_name);
 }
 
 void SystemInfoAPI::OnListenerRemoved(const EventListenerInfo& details) {
   SystemInfoEventRouter::GetInstance()->RemoveEventListener(details.event_name);
 }
 
 }  // namespace extensions