Separate @viewport from other RuleSet construction.

third_party/WebKit/Source/core/page/Page.cpp

Index: third_party/WebKit/Source/core/page/Page.cpp
diff --git a/third_party/WebKit/Source/core/page/Page.cpp b/third_party/WebKit/Source/core/page/Page.cpp
index d86ece1103a3f24dc760549f799999c57c1e5d3c..845621d217898eaad99fc7919939090b61cac085 100644
--- a/third_party/WebKit/Source/core/page/Page.cpp
+++ b/third_party/WebKit/Source/core/page/Page.cpp
@@ -404,10 +404,8 @@ void Page::settingsChanged(SettingsDelegate::ChangeType changeType) {
     case SettingsDelegate::ViewportRuleChange: {
       if (!mainFrame() || !mainFrame()->isLocalFrame())
         break;
-      Document* doc = toLocalFrame(mainFrame())->document();
-      if (!doc || !doc->styleResolver())
-        break;
-      doc->styleResolver()->viewportStyleResolver()->collectViewportRules();
+      if (Document* doc = toLocalFrame(mainFrame())->document())
+        doc->styleEngine().updateViewport();
     } break;
     case SettingsDelegate::TextTrackKindUserPreferenceChange:
       for (Frame* frame = mainFrame(); frame;