Do not activate system tray bubble by default

ash/accelerators/accelerator_controller_delegate_aura.cc

Index: ash/accelerators/accelerator_controller_delegate_aura.cc
diff --git a/ash/accelerators/accelerator_controller_delegate_aura.cc b/ash/accelerators/accelerator_controller_delegate_aura.cc
index 8cce14cc6943498a3fc38241ccfbedafdffedb66..f8c755b48aa5271ffb998c1331b3f20ade5601c7 100644
--- a/ash/accelerators/accelerator_controller_delegate_aura.cc
+++ b/ash/accelerators/accelerator_controller_delegate_aura.cc
@@ -197,8 +197,11 @@ void HandleShowSystemTrayBubble() {
   base::RecordAction(UserMetricsAction("Accel_Show_System_Tray_Bubble"));
   RootWindowController* controller =
       RootWindowController::ForTargetRootWindow();
-  if (!controller->GetSystemTray()->HasSystemBubble())
-    controller->GetSystemTray()->ShowDefaultView(BUBBLE_CREATE_NEW);
+  SystemTray* tray = controller->GetSystemTray();
+  if (!tray->HasSystemBubble()) {
+    tray->ShowDefaultView(BUBBLE_CREATE_NEW);
+    tray->ActivateBubble();
+  }
 }
 
 void HandleTakeWindowScreenshot(ScreenshotDelegate* screenshot_delegate) {