blink: Enable the GPU trigger when viewport meta tag is not read

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 3281 matching lines @@
         newPageScaleFactor = m_pageScaleConstraintsSet.finalConstraints().initialScale;
         m_pageScaleConstraintsSet.setNeedsReset(false);
     }
     setPageScaleFactor(newPageScaleFactor);
 
     updateLayerTreeViewport();
 }
 
 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 (!settings()->viewportEnabled() || !page() || (!m_size.width && !m_size.height) || !page()->mainFrame()->isLocalFrame())
         return;
 
     Document* document = page()->deprecatedLocalMainFrame()->document();
 
     m_matchesHeuristicsForGpuRasterization = description.matchesHeuristicsForGpuRasterization();
     if (m_layerTreeView)
         m_layerTreeView->heuristicsForGpuRasterizationUpdated(m_matchesHeuristicsForGpuRasterization);
 
     Length defaultMinWidth = document->viewportDefaultMinWidth();
@@ skipping 1154 matching lines @@
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 void WebViewImpl::forceNextWebGLContextCreationToFail()
 {
     WebGLRenderingContext::forceNextWebGLContextCreationToFail();
 }
 
 } // namespace blink