Add hasViewportRule() flag to StyleSheetContents.

third_party/WebKit/Source/core/css/StyleRule.h

Index: third_party/WebKit/Source/core/css/StyleRule.h
diff --git a/third_party/WebKit/Source/core/css/StyleRule.h b/third_party/WebKit/Source/core/css/StyleRule.h
index 1cfe952aee2ffaf2da6f2f76c598554c86f03136..db4533d97373d03a4c629f14efaad15e85537d43 100644
--- a/third_party/WebKit/Source/core/css/StyleRule.h
+++ b/third_party/WebKit/Source/core/css/StyleRule.h
@@ -176,7 +176,7 @@ class StyleRulePage : public StyleRuleBase {
   CSSSelectorList m_selectorList;
 };
 
-class StyleRuleGroup : public StyleRuleBase {
+class CORE_EXPORT StyleRuleGroup : public StyleRuleBase {
  public:
   const HeapVector<Member<StyleRuleBase>>& childRules() const {
     return m_childRules;
@@ -195,7 +195,7 @@ class StyleRuleGroup : public StyleRuleBase {
   HeapVector<Member<StyleRuleBase>> m_childRules;
 };
 
-class StyleRuleMedia : public StyleRuleGroup {
+class CORE_EXPORT StyleRuleMedia : public StyleRuleGroup {
  public:
   static StyleRuleMedia* create(MediaQuerySet* media,
                                 HeapVector<Member<StyleRuleBase>>& adoptRules) {