chromeos: Show onscreen bubble when brightness changes.

chrome/browser/chromeos/cros/brightness_library.cc

+// Copyright (c) 2010 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/message_loop.h"
+#include "base/observer_list.h"
+#include "chrome/browser/browser_thread.h"
+#include "chrome/browser/chromeos/brightness_bubble.h"
+#include "chrome/browser/chromeos/volume_bubble.h"
+#include "chrome/browser/chromeos/cros/cros_library.h"
+
+namespace chromeos {
+
+class BrightnessLibraryImpl : public BrightnessLibrary {
+ public:
+  BrightnessLibraryImpl() : brightness_connection_(NULL) {
+    if (CrosLibrary::Get()->EnsureLoaded())
+      Init();
+  }
+
+  ~BrightnessLibraryImpl() {
+    if (brightness_connection_) {
+      chromeos::DisconnectBrightness(brightness_connection_);
+      brightness_connection_ = NULL;
+    }
+  }
+
+  void AddObserver(Observer* observer) {
+    observers_.AddObserver(observer);
+  }
+
+  void RemoveObserver(Observer* observer) {
+    observers_.RemoveObserver(observer);
+  }
+
+ private:
+  static void BrightnessChangedHandler(void* object,
+                                       int brightness_level) {
+    BrightnessLibraryImpl* self = static_cast<BrightnessLibraryImpl*>(object);
+    self->OnBrightnessChanged(brightness_level);
+  }
+
+  void Init() {
+    DCHECK(!brightness_connection_) << "Already intialized";
+    brightness_connection_ =
+        chromeos::MonitorBrightness(&BrightnessChangedHandler, this);
+  }
+
+  void OnBrightnessChanged(int brightness_level) {
+    // 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));
+      return;
+    }
+
+    FOR_EACH_OBSERVER(Observer,
+                      observers_,
+                      BrightnessChanged(brightness_level));
+  }
+
+  chromeos::BrightnessConnection brightness_connection_;
+
+  ObserverList<Observer> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(BrightnessLibraryImpl);
+};
+
+class BrightnessLibraryStubImpl : public BrightnessLibrary {
+ public:
+  BrightnessLibraryStubImpl() {}
+  ~BrightnessLibraryStubImpl() {}
+  void AddObserver(Observer* observer) {}
+  void RemoveObserver(Observer* observer) {}
+};
+
+// static
+BrightnessLibrary* BrightnessLibrary::GetImpl(bool stub) {
+  if (stub)
+    return new BrightnessLibraryStubImpl();
+  else
+    return new BrightnessLibraryImpl();
+}
+
+}  // namespace chromeos
+
+// Allows InvokeLater without adding refcounting. This class is a Singleton and

[glotov, 2010/12/09 18:46:13]

What is 'InvokeLater' here?

+// won't be deleted until its last InvokeLater is run.
+DISABLE_RUNNABLE_METHOD_REFCOUNT(chromeos::BrightnessLibraryImpl);