Trigger style recalc when the window's active state change

Source/core/editing/FrameSelection.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1446 matching lines @@
 void FrameSelection::notifyEventHandlerForSelectionChange()
 {
     m_frame->eventHandler().notifySelectionChanged();
 }
 
 void FrameSelection::focusedOrActiveStateChanged()
 {
     bool activeAndFocused = isFocusedAndActive();
 
     RefPtrWillBeRawPtr<Document> document = m_frame->document();
+    // Invalidate All CustomScrollbars as CustomScrollbars supports
+    // CSS window-active attribute.
+    if (FrameView* view = document->view())
+        view->invalidateAllCustomScrollbarsOnActiveChanged();
+
     document->updateRenderTreeIfNeeded();
 
     // Because RenderObject::selectionBackgroundColor() and
     // RenderObject::selectionForegroundColor() check if the frame is active,
     // we have to update places those colors were painted.
     if (RenderView* view = document->renderView())
         view->invalidatePaintForSelection();
 
     // Caret appears in the active frame.
     if (activeAndFocused)
@@ skipping 479 matching lines @@
     sel.showTreeForThis();
 }
 
 void showTree(const blink::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
 }
 
 #endif