Aura tooltips do not move on mouse move in case of many neighboring views with the same label

ui/wm/public/tooltip_client.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_WM_PUBLIC_TOOLTIP_CLIENT_H_
 #define UI_WM_PUBLIC_TOOLTIP_CLIENT_H_
 
 #include "ui/aura/aura_export.h"
 #include "ui/gfx/font.h"
 
@@ skipping 18 matching lines @@
   virtual void SetTooltipsEnabled(bool enable) = 0;
 
  private:
   friend class ScopedTooltipDisabler;
 };
 
 AURA_EXPORT void SetTooltipClient(Window* root_window,
                                   TooltipClient* client);
 AURA_EXPORT TooltipClient* GetTooltipClient(Window* root_window);
 
-AURA_EXPORT void SetTooltipText(Window* window, base::string16* tooltip_text);
+// Sets the |tooltip_text| and |id| pointers as properties of the |window|.

[sky, 2014/06/02 15:39:47]

This is rather confusing. How about:
Sets the text for the tooltip. The id is used to determine uniqueness when the
text does not change. For example, if the tooltip text does not change, but the
id does then the position of the tooltip is updated.

+// Those are later retrievable by GetTooltipText and GetTooltip id, given
+// the appropriate window pointer. |id| is optionally non-null and is used as
+// an uniqueness indicator for different tooltips - in case its value changes
+// between two points, the tooltips at these two points are treated as separate
+// entities.
+AURA_EXPORT void SetTooltipText(Window* window,
+                                base::string16* tooltip_text);
+AURA_EXPORT void UpdateTooltipId(Window* window, void* id);
 AURA_EXPORT const base::string16 GetTooltipText(Window* window);
+AURA_EXPORT const void* GetTooltipId(Window* window);
 
 }  // namespace client
 }  // namespace aura
 
 #endif  // UI_WM_PUBLIC_TOOLTIP_CLIENT_H_