Error event shouldn't fire when image is updated on environment changes.

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 1953 matching lines @@
 
     sendResizeEventIfNeeded();
 }
 
 bool FrameView::wasViewportResized()
 {
     ASSERT(m_frame);
     RenderView* renderView = this->renderView();
     if (!renderView)
         return false;
+    ASSERT(renderView->style());

[Mike West, 2014/10/17 14:12:40]

Seems unrelated to this CL. Perhaps split it out for clarity?

     return (layoutSize(IncludeScrollbars) != m_lastViewportSize || renderView->style()->zoom() != m_lastZoomFactor);
 }
 
 void FrameView::sendResizeEventIfNeeded()
 {
     ASSERT(m_frame);
 
     RenderView* renderView = this->renderView();
     if (!renderView || renderView->document().printing())
         return;
@@ skipping 1052 matching lines @@
     IntSize visibleSize = expandedIntSize(visibleContentSizeF);
 
     IntPoint maximumOffset(
         contentsWidth() - visibleSize.width() - scrollOrigin().x(),
         contentsHeight() - visibleSize.height() - scrollOrigin().y());
     maximumOffset.clampNegativeToZero();
     return maximumOffset;
 }
 
 } // namespace blink