aura: Ask the WindowDelegate before a Window is Focus()ed.

ui/aura/window_delegate.h

Index: ui/aura/window_delegate.h
diff --git a/ui/aura/window_delegate.h b/ui/aura/window_delegate.h
index 034ad8e49edd6a7a94107a415b76418174409cf1..7dbe94018ae56dbf0c12d7ee83184ed380857154 100644
--- a/ui/aura/window_delegate.h
+++ b/ui/aura/window_delegate.h
@@ -58,6 +58,9 @@ class AURA_EXPORT WindowDelegate {
   // attempted for another reason.
   virtual bool ShouldActivate(Event* event) = 0;
 
+  // Returns true of the window can be focused.
+  virtual bool CanFocus() { return true; }

[sadrul, 2011/12/01 21:48:03]

This probably should be pure virtual?

[Ben Goodger (Google), 2011/12/01 22:16:31]

Yes it should. In general, when you are adding the first non-pure virtual method
to an interface, ur doin' it rong.

[sadrul, 2011/12/01 22:18:23]

Yes :) I wanted to confirm the approach looks sane. I will update the patch to
add purity

[sadrul, 2011/12/02 02:25:55]

Done.

+
   // Sent when the window is activated.
   virtual void OnActivated() = 0;