Toggle GPU raster heuristics based on viewportEnabled.

third_party/WebKit/Source/web/WebViewImpl.cpp

Index: third_party/WebKit/Source/web/WebViewImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebViewImpl.cpp b/third_party/WebKit/Source/web/WebViewImpl.cpp
index fd50765a3d526faa0323d6805470ffd402e00f3a..dcde1b1f4fbadfac3acf4710730e3308bab66ee2 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -3428,19 +3428,17 @@ void WebViewImpl::refreshPageScaleFactorAfterLayout()
 
 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;
     }