Use a single ToplevelWindowEventHandler for the ash::Shell

ash/wm/workspace/workspace_event_handler.cc

Index: ash/wm/workspace/workspace_event_handler.cc
diff --git a/ash/wm/workspace/workspace_event_handler.cc b/ash/wm/workspace/workspace_event_handler.cc
index bcd7e9e1d642bc6a238e7217bf8d47cd080108b3..c23c7742e106958c17eee1c90a8f48ed01832f9d 100644
--- a/ash/wm/workspace/workspace_event_handler.cc
+++ b/ash/wm/workspace/workspace_event_handler.cc
@@ -54,8 +54,7 @@ void ToggleMaximizedState(wm::WindowState* window_state) {
 
 namespace internal {
 
-WorkspaceEventHandler::WorkspaceEventHandler(aura::Window* owner)
-    : ToplevelWindowEventHandler(owner) {
+WorkspaceEventHandler::WorkspaceEventHandler() {
 }
 
 WorkspaceEventHandler::~WorkspaceEventHandler() {
@@ -79,10 +78,8 @@ void WorkspaceEventHandler::OnMouseEvent(ui::MouseEvent* event) {
     case ui::ET_MOUSE_PRESSED: {
       // Maximize behavior is implemented as post-target handling so the target
       // can cancel it.
-      if (ui::EventCanceledDefaultHandling(*event)) {
-        ToplevelWindowEventHandler::OnMouseEvent(event);
+      if (ui::EventCanceledDefaultHandling(*event))
         return;
-      }
       wm::WindowState* target_state = wm::GetWindowState(target);
       if (event->flags() & ui::EF_IS_DOUBLE_CLICK &&
           event->IsOnlyLeftMouseButton() &&
@@ -91,6 +88,7 @@ void WorkspaceEventHandler::OnMouseEvent(ui::MouseEvent* event) {
         ash::Shell::GetInstance()->metrics()->RecordUserMetricsAction(
             ash::UMA_TOGGLE_MAXIMIZE_CAPTION_CLICK);
         ToggleMaximizedState(target_state);
+        event->StopPropagation();
       }
       multi_window_resize_controller_.Hide();
       HandleVerticalResizeDoubleClick(target_state, event);
@@ -99,7 +97,6 @@ void WorkspaceEventHandler::OnMouseEvent(ui::MouseEvent* event) {
     default:
       break;
   }
-  ToplevelWindowEventHandler::OnMouseEvent(event);
 }
 
 void WorkspaceEventHandler::OnGestureEvent(ui::GestureEvent* event) {
@@ -123,7 +120,6 @@ void WorkspaceEventHandler::OnGestureEvent(ui::GestureEvent* event) {
           TouchUMA::GESTURE_FRAMEVIEW_TAP);
     }
   }
-  ToplevelWindowEventHandler::OnGestureEvent(event);
 }
 
 void WorkspaceEventHandler::HandleVerticalResizeDoubleClick(
@@ -154,6 +150,7 @@ void WorkspaceEventHandler::HandleVerticalResizeDoubleClick(
                                      target->bounds().width(),
                                      work_area.height()));
       }
+      event->StopPropagation();
     } else if (component == HTLEFT || component == HTRIGHT) {
       // Don't maximize horizontally if the window has a max width defined.
       if (max_size.width() != 0)
@@ -172,6 +169,7 @@ void WorkspaceEventHandler::HandleVerticalResizeDoubleClick(
                                      work_area.width(),
                                      target->bounds().height()));
       }
+      event->StopPropagation();
     }
   }
 }