Enabled using viewport on desktop browsers behind experimental flag

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 1587 matching lines @@
     FrameView* view = mainFrameImpl()->frameView();
     if (!view)
         return;
 
     WebSize oldSize = m_size;
     float oldPageScaleFactor = pageScaleFactor();
     int oldContentsWidth = contentsSize().width();
 
     m_size = newSize;
 
-    bool shouldAnchorAndRescaleViewport = settings()->viewportEnabled() && oldSize.width && oldContentsWidth;
+    // On devices like phones where a resize comes from screen rotation, we want to
+    // adjust the viewport size so that we don't cause a relayout

[aelias_OOO_until_Jul13, 2013/06/18 01:24:18]

This comment doesn't accurately describe what this is doing: it isn't adjusting
the viewport size or avoiding any relayout.  We're adjusting the scroll position
and page scale to keep content onscreen.

+    bool shouldAnchorAndRescaleViewport = settings()->viewportEnabled()
+        && settings()->resizeAffectsLayoutWidth() && oldSize.width && oldContentsWidth;
+
     ViewportAnchor viewportAnchor(mainFrameImpl()->frame()->eventHandler());
     if (shouldAnchorAndRescaleViewport) {
         viewportAnchor.setAnchor(view->visibleContentRect(),
                                  FloatSize(viewportAnchorXCoord, viewportAnchorYCoord));
     }
 
     // Set the fixed layout size from the viewport constraints before resizing.
     updatePageDefinedPageScaleConstraints(mainFrameImpl()->frame()->document()->viewportArguments());
 
     WebDevToolsAgentPrivate* agentPrivate = devToolsAgentPrivate();
@@ skipping 1393 matching lines @@
 
     if (settingsImpl()->supportDeprecatedTargetDensityDPI())
         m_pageScaleConstraintsSet.adjustPageDefinedConstraintsForAndroidWebView(arguments, m_size, page()->settings()->layoutFallbackWidth(), deviceScaleFactor(), page()->settings()->useWideViewport(), page()->settings()->loadWithOverviewMode());
 
     WebSize layoutSize = flooredIntSize(m_pageScaleConstraintsSet.pageDefinedConstraints().layoutSize);
 
     if (page()->settings() && page()->settings()->textAutosizingEnabled() && page()->mainFrame()
         && layoutSize.width != fixedLayoutSize().width)
             page()->mainFrame()->document()->textAutosizer()->recalculateMultipliers();
 
-    setFixedLayoutSize(layoutSize);
+    // If layoutFallbackWidthIsWindowWidth is set and there's no viewport width set, set the layout size to the window size
+    if (settings()->layoutFallbackWidthIsWindowWidth() && arguments.width == ViewportArguments::ValueAuto)
+        setFixedLayoutSize(m_size);
+    else
+        setFixedLayoutSize(layoutSize);
+
 }
 
 IntSize WebViewImpl::contentsSize() const
 {
     RenderView* root = page()->mainFrame()->contentRenderer();
     if (!root)
         return IntSize();
     return root->documentRect().size();
 }
 
@@ skipping 567 matching lines @@
 {
     if (isNewNavigation)
         *isNewNavigation = m_observedNewNavigation;
 
 #ifndef NDEBUG
     ASSERT(!m_observedNewNavigation
         || m_page->mainFrame()->loader()->documentLoader() == m_newNavigationLoader);
     m_newNavigationLoader = 0;
 #endif
     m_observedNewNavigation = false;
-    if (*isNewNavigation && !isNavigationWithinPage)
+
+    // FIXME: Always need reset when layoutFallbackWidthIsWindowWidth is set
+    // this is a hack to fix some page scaling issues when reloading a page. Why is this needed?

[aelias_OOO_until_Jul13, 2013/06/18 01:24:18]

Instead of doing this, try calling setInitialPageScaleOverride(1) from the
Chromium side and see if that fixes your problem.

[aelias_OOO_until_Jul13, 2013/06/18 01:30:19]

On second thought, that probably won't work.  I don't think this change is the
right fix, whatever the problem is.  You probably should add debug logging
locally to diagnose the issue further: sometimes page scale initialization gets
messed up due to subtle timing issues in when different sizes get initialized.

+    if ((*isNewNavigation && !isNavigationWithinPage) || settings()->layoutFallbackWidthIsWindowWidth())
         m_pageScaleConstraintsSet.setNeedsReset(true);
 
     // Make sure link highlight from previous page is cleared.
     m_linkHighlight.clear();
     m_gestureAnimation.clear();
     if (m_layerTreeView)
         m_layerTreeView->didStopFlinging();
     resetSavedScrollAndScaleState();
 }
 
@@ skipping 479 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