Convert PanelMouseWatcher to have more than one observer.

BUG=None
TEST=PanelMouseWatcherTest.*


Review URL: http://codereview.chromium.org/8677031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@111864 0039d316-1c4b-4281-b951-d872f2087c98

10 files changed, 166 insertions, 46 deletions

diff --git a/chrome/browser/ui/panels/panel_manager.cc b/chrome/browser/ui/panels/panel_manager.cc
index 8480676..1bdaff2 100644
--- a/chrome/browser/ui/panels/panel_manager.cc
+++ b/chrome/browser/ui/panels/panel_manager.cc
@@ -12,6 +12,7 @@
 #include "base/message_loop.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/panels/panel_mouse_watcher.h"
 #include "chrome/browser/ui/window_sizer.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/notification_service.h"
@@ -69,7 +70,7 @@ PanelManager::PanelManager()
       titlebar_action_factory_(this),
       auto_sizing_enabled_(true),
       mouse_watching_disabled_(false) {
-  panel_mouse_watcher_.reset(PanelMouseWatcher::Create(this));
+  panel_mouse_watcher_.reset(PanelMouseWatcher::Create());
   auto_hiding_desktop_bar_ = AutoHidingDesktopBar::Create(this);
   OnDisplayChanged();
 }
@@ -354,7 +355,7 @@ void PanelManager::OnPanelExpansionStateChanged(
 
 void PanelManager::IncrementMinimizedPanels() {
   if (!mouse_watching_disabled_ && !minimized_panel_count_)
-    panel_mouse_watcher_->Start();
+    panel_mouse_watcher_->AddObserver(this);
   minimized_panel_count_++;
   DCHECK_LE(minimized_panel_count_, num_panels());
 }
@@ -363,7 +364,7 @@ void PanelManager::DecrementMinimizedPanels() {
   minimized_panel_count_--;
   DCHECK_GE(minimized_panel_count_, 0);
   if (!mouse_watching_disabled_ && !minimized_panel_count_)
-    panel_mouse_watcher_->Stop();
+    panel_mouse_watcher_->RemoveObserver(this);
 }
 
 void PanelManager::OnPreferredWindowSizeChanged(
diff --git a/chrome/browser/ui/panels/panel_manager.h b/chrome/browser/ui/panels/panel_manager.h
index 5c3a92f..1417798 100644
--- a/chrome/browser/ui/panels/panel_manager.h
+++ b/chrome/browser/ui/panels/panel_manager.h
@@ -13,15 +13,16 @@
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/ui/panels/auto_hiding_desktop_bar.h"
 #include "chrome/browser/ui/panels/panel.h"
-#include "chrome/browser/ui/panels/panel_mouse_watcher.h"
+#include "chrome/browser/ui/panels/panel_mouse_watcher_observer.h"
 #include "ui/gfx/rect.h"
 
 class Browser;
 class Panel;
+class PanelMouseWatcher;
 
 // This class manages a set of panels.
 // Note that the ref count is needed by using PostTask in the implementation.
-class PanelManager : public PanelMouseWatcher::Observer,
+class PanelManager : public PanelMouseWatcherObserver,
                      public AutoHidingDesktopBar::Observer {
  public:
   typedef std::vector<Panel*> Panels;
@@ -79,7 +80,7 @@ class PanelManager : public PanelMouseWatcher::Observer,
   int GetMaxPanelHeight() const;
   int StartingRightPosition() const;
 
-  // Overridden from PanelMouseWatcher::Observer:
+  // Overridden from PanelMouseWatcherObserver:
   virtual void OnMouseMove(const gfx::Point& mouse_position) OVERRIDE;
 
 #ifdef UNIT_TEST
diff --git a/chrome/browser/ui/panels/panel_mouse_watcher.cc b/chrome/browser/ui/panels/panel_mouse_watcher.cc
index dc2ab15..b55ca76 100644
--- a/chrome/browser/ui/panels/panel_mouse_watcher.cc
+++ b/chrome/browser/ui/panels/panel_mouse_watcher.cc
@@ -4,15 +4,29 @@
 
 #include "chrome/browser/ui/panels/panel_mouse_watcher.h"
 
+#include "chrome/browser/ui/panels/panel_mouse_watcher_observer.h"
 #include "ui/gfx/point.h"
 
-PanelMouseWatcher::PanelMouseWatcher(Observer* observer)
-    : observer_(observer) {
+PanelMouseWatcher::PanelMouseWatcher() {
 }
 
 PanelMouseWatcher::~PanelMouseWatcher() {
 }
 
+void PanelMouseWatcher::AddObserver(PanelMouseWatcherObserver* observer) {
+  observers_.AddObserver(observer);
+  if (observers_.size() == 1)
+    Start();
+}
+
+void PanelMouseWatcher::RemoveObserver(PanelMouseWatcherObserver* observer) {
+  DCHECK(observers_.HasObserver(observer));
+  observers_.RemoveObserver(observer);
+  if (observers_.size() == 0)
+    Stop();
+}
+
 void PanelMouseWatcher::NotifyMouseMovement(const gfx::Point& mouse_position) {
-  observer_->OnMouseMove(mouse_position);
+  FOR_EACH_OBSERVER(PanelMouseWatcherObserver, observers_,
+                    OnMouseMove(mouse_position));
 }
diff --git a/chrome/browser/ui/panels/panel_mouse_watcher.h b/chrome/browser/ui/panels/panel_mouse_watcher.h
index d0d6b50..5a36aad 100644
--- a/chrome/browser/ui/panels/panel_mouse_watcher.h
+++ b/chrome/browser/ui/panels/panel_mouse_watcher.h
@@ -4,42 +4,49 @@
 
 #ifndef CHROME_BROWSER_UI_PANELS_PANEL_MOUSE_WATCHER_H_
 #define CHROME_BROWSER_UI_PANELS_PANEL_MOUSE_WATCHER_H_
+#pragma once
+
+#include "base/gtest_prod_util.h"
+#include "base/observer_list.h"
 
 namespace gfx {
 class Point;
 }
 
+class PanelMouseWatcherObserver;
+
 // This is the base class for functionality to watch for mouse movements.
 // The specific implementation of this abstract class differ in how they
 // track mouse movements.
 class PanelMouseWatcher {
  public:
-  // Observer interface for watching mouse movement.
-  class Observer {
-   public:
-    virtual ~Observer() {}
-
-    // Called when the mouse moves.
-    virtual void OnMouseMove(const gfx::Point& mouse_position) = 0;
-  };
-
   // Returns an instance of the platform specific implementation.
-  static PanelMouseWatcher* Create(Observer* observer);
+  static PanelMouseWatcher* Create();
 
   // clang gives an error asking for an out of line destructor.
   virtual ~PanelMouseWatcher();
 
-  // Start/stop tracking mouse movements.
-  virtual void Start() = 0;
-  virtual void Stop() = 0;
+  void AddObserver(PanelMouseWatcherObserver* observer);
+  void RemoveObserver(PanelMouseWatcherObserver* observer);
 
  protected:
-  explicit PanelMouseWatcher(Observer* observer);
+  PanelMouseWatcher();
 
+  // |mouse_position| is in screen coordinates.
   void NotifyMouseMovement(const gfx::Point& mouse_position);
 
+  // Returns true if watching mouse movements.
+  virtual bool IsActive() const = 0;
+
  private:
-  Observer* observer_;
+  friend class PanelMouseWatcherTest;
+  FRIEND_TEST_ALL_PREFIXES(PanelMouseWatcherTest, StartStopWatching);
+
+  // Start/stop tracking mouse movements.
+  virtual void Start() = 0;
+  virtual void Stop() = 0;
+
+  ObserverList<PanelMouseWatcherObserver> observers_;
 };
 
 #endif  // CHROME_BROWSER_UI_PANELS_PANEL_MOUSE_WATCHER_H_
diff --git a/chrome/browser/ui/panels/panel_mouse_watcher_observer.h b/chrome/browser/ui/panels/panel_mouse_watcher_observer.h
new file mode 100644
index 0000000..b76d7c1
--- /dev/null
+++ b/chrome/browser/ui/panels/panel_mouse_watcher_observer.h
@@ -0,0 +1,24 @@
+// 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.
+
+#ifndef CHROME_BROWSER_UI_PANELS_PANEL_MOUSE_WATCHER_OBSERVER_H_
+#define CHROME_BROWSER_UI_PANELS_PANEL_MOUSE_WATCHER_OBSERVER_H_
+#pragma once
+
+namespace gfx {
+class Point;
+}
+
+// This observer interface should be implemented in order to receive
+// notifications from PanelMouseWatcher when the mouse moves.
+class PanelMouseWatcherObserver {
+ public:
+  // Called when the mouse moves.
+  // |mouse_position| is in screen coordinates.
+  virtual void OnMouseMove(const gfx::Point& mouse_position) = 0;
+
+ protected:
+  virtual ~PanelMouseWatcherObserver() {}
+};
+#endif  // CHROME_BROWSER_UI_PANELS_PANEL_MOUSE_WATCHER_OBSERVER_H_
diff --git a/chrome/browser/ui/panels/panel_mouse_watcher_timer.cc b/chrome/browser/ui/panels/panel_mouse_watcher_timer.cc
index 0dcafc3..01a7625 100644
--- a/chrome/browser/ui/panels/panel_mouse_watcher_timer.cc
+++ b/chrome/browser/ui/panels/panel_mouse_watcher_timer.cc
@@ -11,14 +11,14 @@
 // and Mac panels implementations.
 class PanelMouseWatcherTimer : public PanelMouseWatcher {
  public:
-  explicit PanelMouseWatcherTimer(Observer* observer);
+  PanelMouseWatcherTimer();
   virtual ~PanelMouseWatcherTimer();
 
- protected:
-  virtual void Start();
-  virtual void Stop();
-
  private:
+  virtual void Start() OVERRIDE;
+  virtual void Stop() OVERRIDE;
+  virtual bool IsActive() const OVERRIDE;
+
   // Specifies the rate at which we want to sample the mouse position.
   static const int kMousePollingIntervalMs = 250;
 
@@ -36,30 +36,33 @@ class PanelMouseWatcherTimer : public PanelMouseWatcher {
 };
 
 // static
-PanelMouseWatcher* PanelMouseWatcher::Create(Observer* observer) {
-  return new PanelMouseWatcherTimer(observer);
+PanelMouseWatcher* PanelMouseWatcher::Create() {
+  return new PanelMouseWatcherTimer();
 }
 
-PanelMouseWatcherTimer::PanelMouseWatcherTimer(Observer* observer)
-    : PanelMouseWatcher(observer) {
+PanelMouseWatcherTimer::PanelMouseWatcherTimer() {
 }
 
 PanelMouseWatcherTimer::~PanelMouseWatcherTimer() {
-  DCHECK(!timer_.IsRunning());
+  DCHECK(!IsActive());
 }
 
 void PanelMouseWatcherTimer::Start() {
-  DCHECK(!timer_.IsRunning());
+  DCHECK(!IsActive());
   timer_.Start(FROM_HERE,
                base::TimeDelta::FromMilliseconds(kMousePollingIntervalMs),
                this, &PanelMouseWatcherTimer::DoWork);
 }
 
 void PanelMouseWatcherTimer::Stop() {
-  DCHECK(timer_.IsRunning());
+  DCHECK(IsActive());
   timer_.Stop();
 }
 
+bool PanelMouseWatcherTimer::IsActive() const {
+  return timer_.IsRunning();
+}
+
 void PanelMouseWatcherTimer::DoWork() {
   NotifyMouseMovement(gfx::Screen::GetCursorScreenPoint());
 }
diff --git a/chrome/browser/ui/panels/panel_mouse_watcher_unittest.cc b/chrome/browser/ui/panels/panel_mouse_watcher_unittest.cc
new file mode 100755
index 0000000..c9d2ddd
--- /dev/null
+++ b/chrome/browser/ui/panels/panel_mouse_watcher_unittest.cc
@@ -0,0 +1,64 @@
+// 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 "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
+#include "chrome/browser/ui/panels/panel_mouse_watcher.h"
+#include "chrome/browser/ui/panels/panel_mouse_watcher_observer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/point.h"
+
+class TestMouseObserver : public PanelMouseWatcherObserver {
+ public:
+  // Overridden from PanelMouseWatcherObserver:
+  virtual void OnMouseMove(const gfx::Point& mouse_position) OVERRIDE {
+    ++mouse_movements_;
+  }
+  int mouse_movements_;
+};
+
+class PanelMouseWatcherTest : public testing::Test {
+};
+
+TEST_F(PanelMouseWatcherTest, StartStopWatching) {
+  MessageLoop loop(MessageLoop::TYPE_UI);
+
+  scoped_ptr<PanelMouseWatcher> watcher(PanelMouseWatcher::Create());
+  EXPECT_FALSE(watcher->IsActive());
+
+  scoped_ptr<TestMouseObserver> user1(new TestMouseObserver());
+  scoped_ptr<TestMouseObserver> user2(new TestMouseObserver());
+
+  // No observers.
+  watcher->NotifyMouseMovement(gfx::Point(42, 101));
+  EXPECT_EQ(0, user1->mouse_movements_);
+  EXPECT_EQ(0, user2->mouse_movements_);
+
+  // Only one mouse observer.
+  watcher->AddObserver(user1.get());
+  EXPECT_TRUE(watcher->IsActive());
+  watcher->NotifyMouseMovement(gfx::Point(42, 101));
+  EXPECT_GE(user1->mouse_movements_, 1);
+  EXPECT_EQ(0, user2->mouse_movements_);
+  watcher->RemoveObserver(user1.get());
+  EXPECT_FALSE(watcher->IsActive());
+
+  // More than one mouse observer.
+  watcher->AddObserver(user1.get());
+  EXPECT_TRUE(watcher->IsActive());
+  watcher->AddObserver(user2.get());
+  watcher->NotifyMouseMovement(gfx::Point(101, 42));
+  EXPECT_GE(user1->mouse_movements_, 2);
+  EXPECT_GE(user2->mouse_movements_, 1);
+
+  // Back to one observer.
+  watcher->RemoveObserver(user1.get());
+  EXPECT_TRUE(watcher->IsActive());
+  int saved_count = user1->mouse_movements_;
+  watcher->NotifyMouseMovement(gfx::Point(1, 2));
+  EXPECT_EQ(saved_count, user1->mouse_movements_);
+  EXPECT_GE(user2->mouse_movements_, 2);
+  watcher->RemoveObserver(user2.get());
+  EXPECT_FALSE(watcher->IsActive());
+}
diff --git a/chrome/browser/ui/panels/panel_mouse_watcher_win.cc b/chrome/browser/ui/panels/panel_mouse_watcher_win.cc
index 2e91011..9f42b2a 100644
--- a/chrome/browser/ui/panels/panel_mouse_watcher_win.cc
+++ b/chrome/browser/ui/panels/panel_mouse_watcher_win.cc
@@ -27,13 +27,14 @@ HMODULE GetCurrentModuleHandle() {
 
 class PanelMouseWatcherWin : public PanelMouseWatcher {
  public:
-  explicit PanelMouseWatcherWin(Observer* observer);
+  PanelMouseWatcherWin();
   virtual ~PanelMouseWatcherWin();
 
+ private:
   virtual void Start() OVERRIDE;
   virtual void Stop() OVERRIDE;
+  virtual bool IsActive() const OVERRIDE;
 
- private:
   static LRESULT CALLBACK MouseHookProc(int code, WPARAM wparam, LPARAM lparam);
 
   static PanelMouseWatcherWin* instance_;  // singleton instance
@@ -45,34 +46,37 @@ class PanelMouseWatcherWin : public PanelMouseWatcher {
 PanelMouseWatcherWin* PanelMouseWatcherWin::instance_ = NULL;
 
 // static
-PanelMouseWatcher* PanelMouseWatcher::Create(Observer* observer) {
-  return new PanelMouseWatcherWin(observer);
+PanelMouseWatcher* PanelMouseWatcher::Create() {
+  return new PanelMouseWatcherWin();
 }
 
-PanelMouseWatcherWin::PanelMouseWatcherWin(Observer* observer)
-    : PanelMouseWatcher(observer),
-      mouse_hook_(NULL) {
+PanelMouseWatcherWin::PanelMouseWatcherWin()
+    : mouse_hook_(NULL) {
   DCHECK(!instance_);  // Only one instance ever used.
   instance_ = this;
 }
 
 PanelMouseWatcherWin::~PanelMouseWatcherWin() {
-  DCHECK(!mouse_hook_);
+  DCHECK(!IsActive());
 }
 
 void PanelMouseWatcherWin::Start() {
-  DCHECK(!mouse_hook_);
+  DCHECK(!IsActive());
   mouse_hook_ = ::SetWindowsHookEx(
       WH_MOUSE_LL, MouseHookProc, GetCurrentModuleHandle(), 0);
   DCHECK(mouse_hook_);
 }
 
 void PanelMouseWatcherWin::Stop() {
-  DCHECK(mouse_hook_);
+  DCHECK(IsActive());
   ::UnhookWindowsHookEx(mouse_hook_);
   mouse_hook_ = NULL;
 }
 
+bool PanelMouseWatcherWin::IsActive() const {
+  return mouse_hook_ != NULL;
+}
+
 LRESULT CALLBACK PanelMouseWatcherWin::MouseHookProc(int code,
                                                      WPARAM wparam,
                                                      LPARAM lparam) {
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index c26f086..9cdd3a6 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -3191,6 +3191,7 @@
         'browser/ui/panels/panel_manager.h',
         'browser/ui/panels/panel_mouse_watcher.cc',
         'browser/ui/panels/panel_mouse_watcher.h',
+        'browser/ui/panels/panel_mouse_watcher_observer.h',
         'browser/ui/panels/panel_mouse_watcher_timer.cc',
         'browser/ui/panels/panel_mouse_watcher_win.cc',
         'browser/ui/panels/panel_settings_menu_model.cc',
diff --git a/chrome/chrome_tests.gypi b/chrome/chrome_tests.gypi
index 3f2c475..52fddbe 100644
--- a/chrome/chrome_tests.gypi
+++ b/chrome/chrome_tests.gypi
@@ -1863,6 +1863,7 @@
         'browser/ui/omnibox/omnibox_view_unittest.cc',
         'browser/ui/panels/auto_hiding_desktop_bar_win_unittest.cc',
         'browser/ui/panels/panel_browser_window_cocoa_unittest.mm',
+	'browser/ui/panels/panel_mouse_watcher_unittest.cc',
         'browser/ui/search_engines/keyword_editor_controller_unittest.cc',
         'browser/ui/select_file_dialog_unittest.cc',
         'browser/ui/tabs/dock_info_unittest.cc',