cros: Apply the Init() model to BrightnessLibrary API.

chrome/browser/chromeos/cros/brightness_library.cc

 // Copyright (c) 2011 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/chromeos/cros/brightness_library.h"
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/observer_list.h"
 #include "chrome/browser/chromeos/cros/cros_library.h"
 #include "content/browser/browser_thread.h"
 #include "third_party/cros/chromeos_brightness.h"
 
 namespace chromeos {
 
 class BrightnessLibraryImpl : public BrightnessLibrary {
  public:
-  BrightnessLibraryImpl() : brightness_connection_(NULL) {
-    if (CrosLibrary::Get()->EnsureLoaded())
-      Init();
+  BrightnessLibraryImpl() {}

[stevenjb, 2011/07/29 19:19:15]

Still need to initialize brightness_connection_ to NULL

[tfarina, 2011/07/29 19:44:22]

Like in ScreenLockLibraryImpl, we didn't need this because
brightness_connection_ is allocated on the stack.

+
+  ~BrightnessLibraryImpl() {
+    if (brightness_connection_)
+      chromeos::DisconnectBrightness(brightness_connection_);
   }
 
-  ~BrightnessLibraryImpl() {
-    if (brightness_connection_) {
-      chromeos::DisconnectBrightness(brightness_connection_);
-      brightness_connection_ = NULL;
+  void Init() {
+    if (CrosLibrary::Get()->EnsureLoaded()) {
+      DCHECK(!brightness_connection_) << "Already intialized";

[stevenjb, 2011/07/29 19:19:15]

This should either be a CHECK, or we should call DisconnectBrightness on an
existing connection (or just return).

[tfarina, 2011/07/29 19:44:22]

Changed to CHECK.

+      brightness_connection_ =
+          chromeos::MonitorBrightnessV2(&BrightnessChangedHandler, this);
     }
   }
 
+  void AddObserver(Observer* observer) {
+    observers_.AddObserver(observer);
+  }
+
+  void RemoveObserver(Observer* observer) {
+    observers_.RemoveObserver(observer);
+  }
+
   void DecreaseScreenBrightness(bool allow_off) {
     if (chromeos::DecreaseScreenBrightness)
       chromeos::DecreaseScreenBrightness(allow_off);
   }
 
   void IncreaseScreenBrightness() {
     if (chromeos::IncreaseScreenBrightness)
       chromeos::IncreaseScreenBrightness();
   }
 
-  void AddObserver(Observer* observer) {
-    observers_.AddObserver(observer);
-  }
-
-  void RemoveObserver(Observer* observer) {
-    observers_.RemoveObserver(observer);
-  }
-
  private:
   static void BrightnessChangedHandler(void* object,
                                        int brightness_level,
                                        bool user_initiated) {
     BrightnessLibraryImpl* self = static_cast<BrightnessLibraryImpl*>(object);
     self->OnBrightnessChanged(brightness_level, user_initiated);
   }
 
-  void Init() {
-    DCHECK(!brightness_connection_) << "Already intialized";
-    brightness_connection_ =
-        chromeos::MonitorBrightnessV2(&BrightnessChangedHandler, this);
-  }
-
   void OnBrightnessChanged(int brightness_level, bool user_initiated) {
     // Make sure we run on the UI thread.
     if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
       BrowserThread::PostTask(
           BrowserThread::UI, FROM_HERE,
           NewRunnableMethod(this,
                             &BrightnessLibraryImpl::OnBrightnessChanged,
                             brightness_level,
                             user_initiated));
       return;
     }
 
     FOR_EACH_OBSERVER(Observer,
                       observers_,
                       BrightnessChanged(brightness_level, user_initiated));
   }
 
   chromeos::BrightnessConnection brightness_connection_;
 
   ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(BrightnessLibraryImpl);
 };
 
 class BrightnessLibraryStubImpl : public BrightnessLibrary {
  public:
   BrightnessLibraryStubImpl() {}
   ~BrightnessLibraryStubImpl() {}
+  void Init() {}
+  void AddObserver(Observer* observer) {}
+  void RemoveObserver(Observer* observer) {}
   void DecreaseScreenBrightness(bool allow_off) {}
   void IncreaseScreenBrightness() {}
-  void AddObserver(Observer* observer) {}
-  void RemoveObserver(Observer* observer) {}
 };
 
 // static
 BrightnessLibrary* BrightnessLibrary::GetImpl(bool stub) {
+  BrightnessLibrary* impl;
   if (stub)
-    return new BrightnessLibraryStubImpl();
+    impl = new BrightnessLibraryStubImpl();
   else
-    return new BrightnessLibraryImpl();
+    impl = new BrightnessLibraryImpl();
+  impl->Init();
+  return impl;
 }
 
 }  // namespace chromeos
 
 // Needed for NewRunnableMethod() call above.
 DISABLE_RUNNABLE_METHOD_REFCOUNT(chromeos::BrightnessLibraryImpl);