Paint tab-loading throbbers into a ui::Layer.

chrome/browser/ui/views/tabs/tab_controller.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 CHROME_BROWSER_UI_VIEWS_TABS_TAB_CONTROLLER_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_TAB_CONTROLLER_H_
 
 #include "chrome/browser/ui/views/tabs/tab_strip_types.h"
 
 class Tab;
@@ skipping 75 matching lines @@
 
   // Invoked when a mouse event occurs on |source|.
   virtual void OnMouseEventInTab(views::View* source,
                                  const ui::MouseEvent& event) = 0;
 
   // Returns true if |tab| needs to be painted. If false is returned the tab is
   // not painted. If true is returned the tab should be painted and |clip| is
   // set to the clip (if |clip| is empty means no clip).
   virtual bool ShouldPaintTab(const Tab* tab, gfx::Rect* clip) = 0;
 
+  // Returns true if tab loading throbbers can be painted to a composited layer.
+  // This can only be done when the TabController can guarantee that nothing
+  // in the same window will redraw on top of the the favicon area of any tab.
+  virtual bool CanPaintThrobberToLayer() const = 0;
+
   // Returns true if tabs painted in the rectangular light-bar style.
   virtual bool IsImmersiveStyle() const = 0;
 
   // Adds private information to the tab's accessibility state.
   virtual void UpdateTabAccessibilityState(const Tab* tab,
                                         ui::AXViewState* state) = 0;
 
  protected:
   virtual ~TabController() {}
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_TAB_CONTROLLER_H_