Apply RuleSet changes for active stylesheet changes.

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

Index: third_party/WebKit/Source/core/css/ActiveStyleSheets.h
diff --git a/third_party/WebKit/Source/core/css/ActiveStyleSheets.h b/third_party/WebKit/Source/core/css/ActiveStyleSheets.h
index 9febf3f3ac63a623282354c58943a2d80109a317..c17057aa34ac8e23e40355296213fe001c2229c2 100644
--- a/third_party/WebKit/Source/core/css/ActiveStyleSheets.h
+++ b/third_party/WebKit/Source/core/css/ActiveStyleSheets.h
@@ -12,9 +12,11 @@ namespace blink {
 
 class CSSStyleSheet;
 class RuleSet;
+class StyleEngine;
+class TreeScope;
 
-using ActiveStyleSheetVector =
-    HeapVector<std::pair<Member<CSSStyleSheet>, Member<RuleSet>>>;
+using ActiveStyleSheet = std::pair<Member<CSSStyleSheet>, Member<RuleSet>>;
+using ActiveStyleSheetVector = HeapVector<ActiveStyleSheet>;
 
 enum ActiveSheetsChange {
   NoActiveSheetsChanged,  // Nothing changed.
@@ -27,6 +29,12 @@ compareActiveStyleSheets(const ActiveStyleSheetVector& oldStyleSheets,
                          const ActiveStyleSheetVector& newStyleSheets,
                          HeapVector<Member<RuleSet>>& changedRuleSets);
 
+CORE_EXPORT void applyRuleSetChanges(
+    StyleEngine&,
+    TreeScope&,
+    const ActiveStyleSheetVector& oldStyleSheets,
+    const ActiveStyleSheetVector& newStyleSheets);
+
 }  // namespace blink
 
 #endif  // ActiveStyleSheets_h