[Android WebView] Avoid expanding layout width to match the old WebView

Source/core/page/PageScaleConstraintsSet.cpp

 /*
  * Copyright (C) 2013 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
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@@ skipping 118 matching lines @@
 
     float targetDensityDPIFactor = computeDeprecatedTargetDensityDPIFactor(arguments, deviceScaleFactor);
     if (m_pageDefinedConstraints.initialScale != -1)
         m_pageDefinedConstraints.initialScale *= targetDensityDPIFactor;
     m_pageDefinedConstraints.minimumScale *= targetDensityDPIFactor;
     m_pageDefinedConstraints.maximumScale *= targetDensityDPIFactor;
 
     float adjustedLayoutSizeWidth = m_pageDefinedConstraints.layoutSize.width();
     if (useWideViewport && arguments.width == -1 && arguments.zoom != 1.0f)
         adjustedLayoutSizeWidth = layoutFallbackWidth;
+    else if (useWideViewport && arguments.width != -1 && arguments.width != ViewportArguments::ValueDeviceWidth)
+        adjustedLayoutSizeWidth = arguments.width;

[aelias_OOO_until_Jul13, 2013/08/21 20:23:54]

This ends up bypassing every other width computation in ViewportArguments, for
example min-width.  It looks like the only way to do make the behavior change as
narrow as we want is via a parameter used by ViewportArguments::resolve().  

I suggest adding a new enum value to ViewportArguments::resolve,
ViewportMetaSupportingTargetDensityDpi.  Change arguments.type to that in
WebViewImpl::updatePageDefinedPageScaleConstraints by making a local copy of the
object.  Then ViewportArguments::resolve() will already do the right thing
without any further changes (because CSS-device-adaptation standard doesn't want
the weird initial-scale behavior of Safari either).

[mnaganov (inactive), 2013/08/22 08:51:55]

Thanks for the suggestion, Alexandre! I didn't consider adding a new
ViewportArguments type, thinking only of adding an extra argument to ::resolve,
which seemed too ugly, so I resorted to post-patching the value. You approach is
much more creative!

     else {
         if (!useWideViewport)
             adjustedLayoutSizeWidth = getLayoutWidthForNonWideViewport(viewSize, initialScale);
+        else if (arguments.width == ViewportArguments::ValueDeviceWidth || (arguments.width == -1 && arguments.zoom == 1.0f))
+            adjustedLayoutSizeWidth = viewSize.width();
         if (!useWideViewport || arguments.width == -1 || arguments.width == ViewportArguments::ValueDeviceWidth)
             adjustedLayoutSizeWidth /= targetDensityDPIFactor;
     }
 
     ASSERT(m_pageDefinedConstraints.layoutSize.width() > 0);
     float adjustedLayoutSizeHeight = (adjustedLayoutSizeWidth * m_pageDefinedConstraints.layoutSize.height()) / m_pageDefinedConstraints.layoutSize.width();
     m_pageDefinedConstraints.layoutSize.setWidth(adjustedLayoutSizeWidth);
     m_pageDefinedConstraints.layoutSize.setHeight(adjustedLayoutSizeHeight);
 }
 
 } // namespace WebCore