Add a force-layout-height-to-zero layout mode to WebViewImpl

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 3085 matching lines @@
 
     RefPtr<FrameView> view = mainFrameImpl()->frameView();
     if (!view)
         return;
 
     WebSize layoutSize = m_size;
 
     if (settings()->viewportEnabled())
         layoutSize = flooredIntSize(m_pageScaleConstraintsSet.pageDefinedConstraints().layoutSize);
 
+    if (page()->settings().forceZeroLayoutHeight())
+        layoutSize.height = 0;
+
     view->setLayoutSize(layoutSize);
 }
 
 IntSize WebViewImpl::contentsSize() const
 {
     if (!page()->mainFrame()->isLocalFrame())
         return IntSize();
     RenderView* root = page()->deprecatedLocalMainFrame()->contentRenderer();
     if (!root)
         return IntSize();
@@ skipping 1119 matching lines @@
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return false;
 
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace blink