Mixed Content: Implement strict mode.

Source/core/frame/csp/CSPDirectiveList.h

Index: Source/core/frame/csp/CSPDirectiveList.h
diff --git a/Source/core/frame/csp/CSPDirectiveList.h b/Source/core/frame/csp/CSPDirectiveList.h
index f3f474a32aa74c455a1845c2761e20b5e08548f4..b577dc991f124148a7504297e63e815a285e5d1b 100644
--- a/Source/core/frame/csp/CSPDirectiveList.h
+++ b/Source/core/frame/csp/CSPDirectiveList.h
@@ -74,6 +74,7 @@ private:
     void parseReferrer(const String& name, const String& value);
     void addDirective(const String& name, const String& value);
     void applySandboxPolicy(const String& name, const String& sandboxPolicy);
+    void enforceStrictMixedContentChecking(const String& name, const String& value);
 
     template <class CSPDirectiveType>
     void setCSPDirective(const String& name, const String& value, OwnPtr<CSPDirectiveType>&);
@@ -117,6 +118,8 @@ private:
     bool m_didSetReferrerPolicy;
     ReferrerPolicy m_referrerPolicy;
 
+    bool m_strictMixedContentCheckingEnforced;
+
     OwnPtr<MediaListDirective> m_pluginTypes;
     OwnPtr<SourceListDirective> m_baseURI;
     OwnPtr<SourceListDirective> m_childSrc;