chromeos: Enable Alt-Shift-S to show system tray bubble for mash

ash/common/accelerators/accelerator_controller.cc

Index: ash/common/accelerators/accelerator_controller.cc
diff --git a/ash/common/accelerators/accelerator_controller.cc b/ash/common/accelerators/accelerator_controller.cc
index 89c946f59965017fdd1d93f76e90b306fc1b72f4..c30bdad1ce2ebab39262441d025e1381b7714ce4 100644
--- a/ash/common/accelerators/accelerator_controller.cc
+++ b/ash/common/accelerators/accelerator_controller.cc
@@ -28,6 +28,7 @@
 #include "ash/common/system/keyboard_brightness_control_delegate.h"
 #include "ash/common/system/status_area_widget.h"
 #include "ash/common/system/system_notifier.h"
+#include "ash/common/system/tray/system_tray.h"
 #include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/system/tray/system_tray_notifier.h"
 #include "ash/common/system/web_notification/web_notification_tray.h"
@@ -232,6 +233,16 @@ void HandleShowMessageCenterBubble() {
   }
 }
 
+void HandleShowSystemTrayBubble() {
+  base::RecordAction(UserMetricsAction("Accel_Show_System_Tray_Bubble"));
+  WmWindow* target_root = Shell::GetWmRootWindowForNewWindows();
+  SystemTray* tray = target_root->GetRootWindowController()->GetSystemTray();
+  if (!tray->HasSystemBubble()) {
+    tray->ShowDefaultView(BUBBLE_CREATE_NEW);
+    tray->ActivateBubble();
+  }
+}
+
 void HandleShowTaskManager() {
   base::RecordAction(UserMetricsAction("Accel_Show_Task_Manager"));
   WmShell::Get()->new_window_controller()->ShowTaskManager();
@@ -839,6 +850,7 @@ bool AcceleratorController::CanPerformAction(
     case RESTORE_TAB:
     case SHOW_IME_MENU_BUBBLE:
     case SHOW_KEYBOARD_OVERLAY:
+    case SHOW_SYSTEM_TRAY_BUBBLE:
     case SHOW_TASK_MANAGER:
     case SUSPEND:
     case TOGGLE_FULLSCREEN:
@@ -1018,6 +1030,9 @@ void AcceleratorController::PerformAction(AcceleratorAction action,
     case SHOW_STYLUS_TOOLS:
       HandleShowStylusTools();
       break;
+    case SHOW_SYSTEM_TRAY_BUBBLE:
+      HandleShowSystemTrayBubble();
+      break;
     case SHOW_TASK_MANAGER:
       HandleShowTaskManager();
       break;