Enable tooltips for aura.

ui/aura/window.h

Index: ui/aura/window.h
diff --git a/ui/aura/window.h b/ui/aura/window.h
index 57ea1ea251b8c8aac74a5354da3db32d5139aec5..58c1037088864a8fe90789be295ec14391a01e3f 100644
--- a/ui/aura/window.h
+++ b/ui/aura/window.h
@@ -68,6 +68,9 @@ class AURA_EXPORT Window : public ui::LayerDelegate {
   const std::string& name() const { return name_; }
   void set_name(const std::string& name) { name_ = name; }
 
+  const string16& tooltip() const { return tooltip_; }

[Ben Goodger (Google), 2011/10/25 22:24:45]

Seems like at the shell level we are always querying the TTM for the current
text... so we don't need to carry this anywhere...

[varunjain, 2011/10/25 22:35:05]

I am not sure I completely understand. We never query the TTM.. in fact TTM is
the one that queries the window or view currently under the mouse cursor for the
current tooltip.

+  void set_tooltip(const string16& tooltip) { tooltip_ = tooltip; }
+
   ui::Layer* layer() { return layer_.get(); }
   const ui::Layer* layer() const { return layer_.get(); }
 
@@ -318,6 +321,8 @@ class AURA_EXPORT Window : public ui::LayerDelegate {
   int id_;
   std::string name_;
 
+  string16 tooltip_;
+
   scoped_ptr<EventFilter> event_filter_;
   scoped_ptr<LayoutManager> layout_manager_;