Invalidate Custom Scrollbars irrespective of focused frame.

Source/core/page/FocusController.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nuanti Ltd.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 707 matching lines @@
 }
 
 void FocusController::setActive(bool active)
 {
     if (m_isActive == active)
         return;
 
     m_isActive = active;
 
     Frame* frame = focusedOrMainFrame();
-    if (frame->isLocalFrame())
+    if (frame->isLocalFrame()) {
+        // Invalidate all custom scrollbars because they support the CSS
+        // window-active attribute. This should be applied to the entire page so
+        // we invalidate from the root FrameView instead of just the focused.
+        if (FrameView* view = toLocalFrame(frame)->localFrameRoot()->document()->view())
+            view->invalidateAllCustomScrollbarsOnActiveChanged();
         toLocalFrame(frame)->selection().pageActivationChanged();
+    }
 }
 
 static void updateFocusCandidateIfNeeded(FocusType type, const FocusCandidate& current, FocusCandidate& candidate, FocusCandidate& closest)
 {
     ASSERT(candidate.visibleNode->isElementNode());
     ASSERT(candidate.visibleNode->renderer());
 
     // Ignore iframes that don't have a src attribute
     if (frameOwnerElement(candidate) && (!frameOwnerElement(candidate)->contentFrame() || candidate.rect.isEmpty()))
         return;
@@ skipping 182 matching lines @@
     return consumed;
 }
 
 void FocusController::trace(Visitor* visitor)
 {
     visitor->trace(m_page);
     visitor->trace(m_focusedFrame);
 }
 
 } // namespace blink