Toggle GPU raster heuristics based on viewportEnabled.

third_party/WebKit/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 3410 matching lines @@
     // Changes to page-scale during layout may require an additional frame.
     // We can't update the lifecycle here because we may be in the middle of layout in the
     // caller of this method.
     // TODO(chrishtr): clean all this up. All layout should happen in one lifecycle run (crbug.com/578239).
     if (mainFrameImpl()->frameView()->needsLayout())
         mainFrameImpl()->frameWidget()->scheduleAnimation();
 }
 
 void WebViewImpl::updatePageDefinedViewportConstraints(const ViewportDescription& description)
 {
-    // If we're not reading the viewport meta tag, allow GPU rasterization.
-    if (!settingsImpl()->viewportMetaEnabled()) {
-        m_matchesHeuristicsForGpuRasterization = true;
-        if (m_layerTreeView)
-            m_layerTreeView->heuristicsForGpuRasterizationUpdated(m_matchesHeuristicsForGpuRasterization);
-    }
-
     if (!page() || (!m_size.width && !m_size.height) || !page()->mainFrame()->isLocalFrame())
         return;
 
     if (!settings()->viewportEnabled()) {
         pageScaleConstraintsSet().clearPageDefinedConstraints();
         updateMainFrameLayoutSize();
+
+        // If we don't support mobile viewports, allow GPU rasterization.
+        m_matchesHeuristicsForGpuRasterization = true;
+        if (m_layerTreeView)
+            m_layerTreeView->heuristicsForGpuRasterizationUpdated(m_matchesHeuristicsForGpuRasterization);
         return;
     }
 
     Document* document = page()->deprecatedLocalMainFrame()->document();
 
     m_matchesHeuristicsForGpuRasterization = description.matchesHeuristicsForGpuRasterization();
     if (m_layerTreeView)
         m_layerTreeView->heuristicsForGpuRasterizationUpdated(m_matchesHeuristicsForGpuRasterization);
 
     Length defaultMinWidth = document->viewportDefaultMinWidth();
@@ skipping 1162 matching lines @@
         return nullptr;
     return focusedFrame;
 }
 
 LocalFrame* WebViewImpl::focusedLocalFrameAvailableForIme() const
 {
     return m_imeAcceptEvents ? focusedLocalFrameInWidget() : nullptr;
 }
 
 } // namespace blink