Mac: improve apparent z-order problems when switching Spaces.

chrome/browser/cocoa/status_bubble_mac.h

Index: chrome/browser/cocoa/status_bubble_mac.h
diff --git a/chrome/browser/cocoa/status_bubble_mac.h b/chrome/browser/cocoa/status_bubble_mac.h
index 8d33f04553d1de1d9e436600d5a874575cf17f21..e43b81fd5c43cb87a9e24acc3a58e6a9c2d0037a 100644
--- a/chrome/browser/cocoa/status_bubble_mac.h
+++ b/chrome/browser/cocoa/status_bubble_mac.h
@@ -63,9 +63,17 @@ class StatusBubbleMac : public StatusBubble {
   // it does.)
   void Create();
 
-  // Attaches the status bubble window to its parent window.
+  // Attaches the status bubble window to its parent window. Safe to call even
+  // when already attached.
   void Attach();
 
+  // Detaches the status bubble window from its parent window.
+  void Detach();
+
+  // Is the status bubble attached to the browser window? It should be attached
+  // when shown and during any fades, but should be detached when hidden.
+  bool is_attached() { return [window_ parentWindow] != nil; }
+
   // Begins fading the status bubble window in or out depending on the value
   // of |show|.  This must be called from the appropriate fade state,
   // kBubbleShowingFadeIn or kBubbleHidingFadeOut, or from the appropriate