Fix tab dragging in unity2d

ui/base/x/x11_util.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 UI_BASE_X_X11_UTIL_H_
 #define UI_BASE_X_X11_UTIL_H_
 
 // This file declares utility functions for X11 (Linux only).
 //
 // These functions do not require the Xlib headers to be included (which is why
@@ skipping 127 matching lines @@
 
 // Return the number of bits-per-pixel for a pixmap of the given depth
 UI_EXPORT int BitsPerPixelForPixmapDepth(Display* display, int depth);
 
 // Returns true if |window| is visible.
 UI_EXPORT bool IsWindowVisible(XID window);
 
 // Returns the bounds of |window|.
 UI_EXPORT bool GetWindowRect(XID window, gfx::Rect* rect);
 
+// Returns true if |window| contains the point |screen_loc|.
+UI_EXPORT bool WindowContainsPoint(XID window, gfx::Point screen_loc);
+
 // Return true if |window| has any property with |property_name|.
 UI_EXPORT bool PropertyExists(XID window, const std::string& property_name);
 
 // Get the value of an int, int array, atom array or string property.  On
 // success, true is returned and the value is stored in |value|.
 UI_EXPORT bool GetIntProperty(XID window, const std::string& property_name,
                               int* value);
 UI_EXPORT bool GetIntArrayProperty(XID window, const std::string& property_name,
                                    std::vector<int>* value);
 UI_EXPORT bool GetAtomArrayProperty(XID window,
@@ skipping 210 matching lines @@
  private:
   ::Cursor cursor_;
   Display* display_;
 
   DISALLOW_COPY_AND_ASSIGN(XScopedCursor);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_X_X11_UTIL_H_