Separate @viewport from other RuleSet construction.

third_party/WebKit/Source/core/dom/StyleEngine.cpp

Index: third_party/WebKit/Source/core/dom/StyleEngine.cpp
diff --git a/third_party/WebKit/Source/core/dom/StyleEngine.cpp b/third_party/WebKit/Source/core/dom/StyleEngine.cpp
index 8d064daae7b4616bf5b20da5bfe97e7391e6d664..6ff6b18a295c537935e2ef94d45f731e93831b29 100644
--- a/third_party/WebKit/Source/core/dom/StyleEngine.cpp
+++ b/third_party/WebKit/Source/core/dom/StyleEngine.cpp
@@ -37,6 +37,7 @@
 #include "core/css/StyleSheetContents.h"
 #include "core/css/invalidation/InvalidationSet.h"
 #include "core/css/resolver/ScopedStyleResolver.h"
+#include "core/css/resolver/ViewportStyleResolver.h"
 #include "core/dom/DocumentStyleSheetCollector.h"
 #include "core/dom/Element.h"
 #include "core/dom/ElementTraversal.h"
@@ -393,6 +394,8 @@ void StyleEngine::shadowRootRemovedFromDocument(ShadowRoot* shadowRoot) {
 void StyleEngine::appendActiveAuthorStyleSheets() {
   DCHECK(isMaster());
 
+  documentStyleSheetCollection().updateViewport();
+
   m_resolver->appendAuthorStyleSheets(
       documentStyleSheetCollection().activeAuthorStyleSheets());
   for (TreeScope* treeScope : m_activeTreeScopes) {
@@ -442,6 +445,7 @@ void StyleEngine::clearMasterResolver() {
 
 void StyleEngine::didDetach() {
   clearResolver();
+  m_viewportResolver.clear();
 }
 
 bool StyleEngine::shouldClearResolver() const {
@@ -499,6 +503,12 @@ void StyleEngine::removeFontFaceRules(
     m_resolver->invalidateMatchedPropertiesCache();
 }
 
+ViewportStyleResolver& StyleEngine::ensureViewportStyleResolver() {
+  if (!m_viewportResolver)
+    m_viewportResolver = ViewportStyleResolver::create(m_document);
+  return *m_viewportResolver.get();
+}
+
 void StyleEngine::markTreeScopeDirty(TreeScope& scope) {
   if (scope == m_document) {
     markDocumentDirty();
@@ -947,6 +957,12 @@ void StyleEngine::ensureFullscreenUAStyle() {
     m_resolver->resetRuleFeatures();
 }
 
+void StyleEngine::initialViewportChanged() {
+  if (m_viewportResolver &&
+      m_viewportResolver->isAffectedByInitialViewportChange())
+    updateViewport();
+}
+
 DEFINE_TRACE(StyleEngine) {
   visitor->trace(m_document);
   visitor->trace(m_injectedAuthorStyleSheets);
@@ -954,6 +970,7 @@ DEFINE_TRACE(StyleEngine) {
   visitor->trace(m_documentStyleSheetCollection);
   visitor->trace(m_styleSheetCollectionMap);
   visitor->trace(m_resolver);
+  visitor->trace(m_viewportResolver);
   visitor->trace(m_styleInvalidator);
   visitor->trace(m_dirtyTreeScopes);
   visitor->trace(m_activeTreeScopes);