[Android WebView] Treat zero values in viewport arguments specially

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 2911 matching lines @@
 void Document::processViewport(const String& features, ViewportArguments::Type origin)
 {
     ASSERT(!features.isNull());
 
     if (origin < m_viewportArguments.type)
         return;
 
     m_viewportArguments = ViewportArguments(origin);
     processArguments(features, (void*)&m_viewportArguments, &setViewportFeature);
 
+    if (page() && page()->settings().viewportMetaZeroValuesQuirk() && m_viewportArguments.type == ViewportArguments::ViewportMeta
+        && m_viewportArguments.width == ViewportArguments::ValueDeviceWidth && !static_cast<int>(m_viewportArguments.zoom))
+        m_viewportArguments.zoom = 1.0;
+
     updateViewportArguments();
 }
 
 void Document::updateViewportArguments()
 {
     if (page() && page()->mainFrame() == frame()) {
 #ifndef NDEBUG
         m_didDispatchViewportPropertiesChanged = true;
 #endif
         page()->chrome().dispatchViewportPropertiesDidChange(m_viewportArguments);
@@ skipping 2352 matching lines @@
 {
     return DocumentLifecycleNotifier::create(this);
 }
 
 DocumentLifecycleNotifier* Document::lifecycleNotifier()
 {
     return static_cast<DocumentLifecycleNotifier*>(ScriptExecutionContext::lifecycleNotifier());
 }
 
 } // namespace WebCore