Prevents double-clicks on a tab close button from aslo maximizing the browser

ash/wm/workspace/workspace_event_handler.h

 // Copyright (c) 2012 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.
 
 #ifndef ASH_WM_WORKSPACE_WORKSPACE_EVENT_HANDLER_H_
 #define ASH_WM_WORKSPACE_WORKSPACE_EVENT_HANDLER_H_
 
 #include "ash/wm/workspace/multi_window_resize_controller.h"
 #include "ui/events/event_handler.h"
 
@@ skipping 20 matching lines @@
 
   // Determines if |event| corresponds to a double click on either the top or
   // bottom vertical resize edge, and if so toggles the vertical height of the
   // window between its restored state and the full available height of the
   // workspace.
   void HandleVerticalResizeDoubleClick(wm::WindowState* window_state,
                                        ui::MouseEvent* event);
 
   MultiWindowResizeController multi_window_resize_controller_;
 
+  // The non-client component for the target of a MouseEvent or GestureEvent.
+  // Events can be destructive to the window tree, which can cause the
+  // component of a ui::EF_IS_DOUBLE_CLICK event to no longer be the same as
+  // that of the initial click. Acting on a double click should only occur for
+  // matching components.
+  int event_target_component_;
+
   DISALLOW_COPY_AND_ASSIGN(WorkspaceEventHandler);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_WORKSPACE_WORKSPACE_EVENT_HANDLER_H_