[Test]Swiping on system tray bubble.

ash/system/tray/system_tray_bubble.cc

Index: ash/system/tray/system_tray_bubble.cc
diff --git a/ash/system/tray/system_tray_bubble.cc b/ash/system/tray/system_tray_bubble.cc
index bf94470ed85f0c75f6784d3d8513fc6c2e1cc0de..4f4160a4408d3e568f9846e3fb379c801e541ddb 100644
--- a/ash/system/tray/system_tray_bubble.cc
+++ b/ash/system/tray/system_tray_bubble.cc
@@ -197,8 +197,22 @@ void SystemTrayBubble::InitView(views::View* anchor,
   }
 
   init_params->delegate = tray_;
-  // Place the bubble on same display as this system tray.
-  init_params->parent_window = tray_->GetBubbleWindowContainer();
+  // Place the bubble on same display as this system tray if it is not on
+  // maximize mode. Otherwise, create an clipping window to hold the system
+  // bubble. And place the clipping window on the same display as the system
+  // tray.
+  if (tray_->on_maximize_mode()) {
+    aura::Window* clipping_window = new aura::Window(nullptr);
+    clipping_window->Init(ui::LAYER_NOT_DRAWN);
+    clipping_window->layer()->SetMasksToBounds(true);
+    clipping_window->SetBounds(tray_->GetWorkAreaBoundsInScreen());
+    tray_->GetBubbleWindowContainer()->AddChild(clipping_window);
+    clipping_window->Show();
+    init_params->parent_window = clipping_window;
+  } else {
+    init_params->parent_window = tray_->GetBubbleWindowContainer();
+  }
+
   init_params->anchor_view = anchor;
   bubble_view_ = new TrayBubbleView(*init_params);
   UpdateBottomPadding();