Make tooltips toplevel windows on Linux

ui/views/corewm/tooltip_aura.h

Index: ui/views/corewm/tooltip_aura.h
diff --git a/ui/views/corewm/tooltip_aura.h b/ui/views/corewm/tooltip_aura.h
index dfbd9a893d2e1c773bdc144a45eb841cc4ab3097..ead119f5d95889c4a1e2e5fc1a5f72f4d807ef4c 100644
--- a/ui/views/corewm/tooltip_aura.h
+++ b/ui/views/corewm/tooltip_aura.h
@@ -40,18 +40,12 @@ class VIEWS_EXPORT TooltipAura : public Tooltip, public WidgetObserver {
   // Returns the max width of the tooltip when shown at the specified location.
   int GetMaxWidth(const gfx::Point& location) const;
 
-  // Returns the bounds to fit the tooltip in.
-  gfx::Rect GetBoundsForTooltip(const gfx::Point& origin) const;
-
   // Adjusts the bounds given by the arguments to fit inside the desktop
   // and applies the adjusted bounds to the label_.
   void SetTooltipBounds(const gfx::Point& mouse_pos,
                         int tooltip_width,
                         int tooltip_height);
 
-  // Makes sure |widget_| is valid, creating as necessary.
-  void CreateWidget();
-
   // Destroys |widget_|.
   void DestroyWidget();