[Android WebView] Update viewport size and scale calculation to match WebView Classic

Source/WebKit/chromium/src/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 3029 matching lines @@
         if (!contentsSize().width() || !m_size.width)
             return;
 
         // When viewport tag is enabled, the scale needed to see the full
         // content width is the default minimum.
         int viewWidthNotIncludingScrollbars = m_size.width;
         if (view->verticalScrollbar() && !view->verticalScrollbar()->isOverlayScrollbar())
             viewWidthNotIncludingScrollbars -= view->verticalScrollbar()->width();
         m_minimumPageScaleFactor = max(m_minimumPageScaleFactor, static_cast<float>(viewWidthNotIncludingScrollbars) / contentsSize().width());
         m_maximumPageScaleFactor = max(m_minimumPageScaleFactor, m_maximumPageScaleFactor);
+        if (m_initialPageScaleFactorOverride != -1) {
+            m_minimumPageScaleFactor = min(m_minimumPageScaleFactor, m_initialPageScaleFactorOverride);
+            m_maximumPageScaleFactor = max(m_maximumPageScaleFactor, m_initialPageScaleFactorOverride);
+        }
     }
     ASSERT(m_minimumPageScaleFactor <= m_maximumPageScaleFactor);
 
     // Initialize and/or clamp the page scale factor if needed.
     float initialPageScaleFactor = m_initialPageScaleFactor;
     if (!settings()->viewportEnabled())
         initialPageScaleFactor = 1;
     if (m_initialPageScaleFactorOverride != -1)
         initialPageScaleFactor = m_initialPageScaleFactorOverride;
     float newPageScaleFactor = pageScaleFactor();
@@ skipping 1131 matching lines @@
 }
 
 bool WebViewImpl::shouldDisableDesktopWorkarounds()
 {
     ViewportArguments arguments = mainFrameImpl()->frame()->document()->viewportArguments();
     return arguments.width == ViewportArguments::ValueDeviceWidth || !arguments.userZoom
         || (arguments.minZoom == arguments.maxZoom && arguments.minZoom != ViewportArguments::ValueAuto);
 }
 
 } // namespace WebKit