Remove useless code to invalidate rects on the HostWindow. It's a no-op for frames.

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 355 matching lines @@
     setScrollbarsSuppressed(true);
 }
 
 bool FrameView::didFirstLayout() const
 {
     return !m_firstLayout;
 }
 
 void FrameView::invalidateRect(const IntRect& rect)
 {
-    if (!parent()) {
-        if (HostWindow* window = getHostWindow())
-            window->invalidateRect(rect);
-        return;
-    }
-
     LayoutPartItem layoutItem = m_frame->ownerLayoutItem();
     if (layoutItem.isNull())
         return;
 
     IntRect paintInvalidationRect = rect;
     paintInvalidationRect.move(layoutItem.borderLeft() + layoutItem.paddingLeft(),
         layoutItem.borderTop() + layoutItem.paddingTop());
     // FIXME: We should not allow paint invalidation out of paint invalidation state. crbug.com/457415
     DisablePaintInvalidationStateAsserts paintInvalidationAssertDisabler;
     layoutItem.invalidatePaintRectangle(LayoutRect(paintInvalidationRect));
@@ skipping 3889 matching lines @@
 }
 
 bool FrameView::canThrottleRendering() const
 {
     if (!RuntimeEnabledFeatures::renderingPipelineThrottlingEnabled())
         return false;
     return m_subtreeThrottled || (m_hiddenForThrottling && m_crossOriginForThrottling);
 }
 
 } // namespace blink