Switch ObserverList::size() to ObserverList::might_have_observers() Pt.1

chrome/browser/ui/panels/display_settings_provider.cc

 // Copyright (c) 2012 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/ui/panels/display_settings_provider.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "chrome/browser/fullscreen.h"
 #include "ui/gfx/screen.h"
@@ skipping 25 matching lines @@
 }
 
 void DisplaySettingsProvider::RemoveDesktopBarObserver(
     DesktopBarObserver* observer) {
   desktop_bar_observers_.RemoveObserver(observer);
 }
 
 void DisplaySettingsProvider::AddFullScreenObserver(
     FullScreenObserver* observer) {
   is_full_screen_ = IsFullScreen();
+  bool already_started = full_screen_observers_.might_have_observers();
   full_screen_observers_.AddObserver(observer);
 
-  if (full_screen_observers_.size() == 1 && NeedsPeriodicFullScreenCheck()) {
+  if (!already_started && NeedsPeriodicFullScreenCheck()) {
     full_screen_mode_timer_.Start(FROM_HERE,
         base::TimeDelta::FromMilliseconds(kFullScreenModeCheckIntervalMs),
         base::Bind(&DisplaySettingsProvider::CheckFullScreenMode,
                    base::Unretained(this),
                    PERFORM_FULLSCREEN_CHECK));
   }
 }
 
 void DisplaySettingsProvider::RemoveFullScreenObserver(
     FullScreenObserver* observer) {
   full_screen_observers_.RemoveObserver(observer);
 
-  if (full_screen_observers_.size() == 0)
+  if (!full_screen_observers_.might_have_observers())
     full_screen_mode_timer_.Stop();
 }
 
 // TODO(scottmg): This should be moved to ui/.
 gfx::Rect DisplaySettingsProvider::GetPrimaryDisplayArea() const {
   // TODO(scottmg): NativeScreen is wrong. http://crbug.com/133312
   return gfx::Screen::GetNativeScreen()->GetPrimaryDisplay().bounds();
 }
 
 gfx::Rect DisplaySettingsProvider::GetPrimaryWorkArea() const {
@@ skipping 87 matching lines @@
 bool DisplaySettingsProvider::IsFullScreen() {
   return IsFullScreenMode();
 }
 
 #if defined(USE_AURA)
 // static
 DisplaySettingsProvider* DisplaySettingsProvider::Create() {
   return new DisplaySettingsProvider();
 }
 #endif