Add UI for cast system tray integration

ash/system/chromeos/screen_security/screen_capture_tray_item.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 "ash/system/chromeos/screen_security/screen_capture_tray_item.h"
 
 #include "ash/shell.h"
 #include "ash/system/system_notifier.h"
 #include "grit/ash_resources.h"
 #include "grit/ash_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/notification.h"
 
 using message_center::Notification;
 
 namespace ash {
 namespace {
 
 const char kScreenCaptureNotificationId[] = "chrome://screen/capture";
 
 }  // namespace
 
 ScreenCaptureTrayItem::ScreenCaptureTrayItem(SystemTray* system_tray)
     : ScreenTrayItem(system_tray) {
+  Shell::GetInstance()->AddShellObserver(this);
   Shell::GetInstance()->system_tray_notifier()->
       AddScreenCaptureObserver(this);
 }
 
 ScreenCaptureTrayItem::~ScreenCaptureTrayItem() {
+  Shell::GetInstance()->RemoveShellObserver(this);
   Shell::GetInstance()->system_tray_notifier()->
       RemoveScreenCaptureObserver(this);
 }
 
 views::View* ScreenCaptureTrayItem::CreateTrayView(user::LoginStatus status) {
   set_tray_view(
       new tray::ScreenTrayView(this, IDR_AURA_UBER_TRAY_SCREENSHARE));
   return tray_view();
 }
 
@@ skipping 30 matching lines @@
 }
 
 std::string ScreenCaptureTrayItem::GetNotificationId() {
   return kScreenCaptureNotificationId;
 }
 
 void ScreenCaptureTrayItem::OnScreenCaptureStart(
     const base::Closure& stop_callback,
     const base::string16& screen_capture_status) {
   screen_capture_status_ = screen_capture_status;
+
+  // We do not want to show the screen capture tray item and the chromecast
+  // casting tray item at the same time. We will hide this tray item.
+  //
+  // This suppression technique is currently dependent on the order
+  // that OnScreenCaptureStart and OnCastingSessionStartedOrStopped
+  // get invoked. OnCastingSessionStartedOrStopped currently gets
+  // called first.
+  if (is_casting_)
+    return;
+
   Start(stop_callback);
 }
 
 void ScreenCaptureTrayItem::OnScreenCaptureStop() {
   // We do not need to run the stop callback when
   // screen capture is stopped externally.
   set_is_started(false);
   Update();
 }
 
+void ScreenCaptureTrayItem::OnCastingSessionStartedOrStopped(bool started) {
+  is_casting_ = started;
+}
+
 }  // namespace ash