Part 5.1: Is policy list subsumed under subsuming policy?

third_party/WebKit/Source/core/frame/csp/MediaListDirective.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MediaListDirective_h
 #define MediaListDirective_h
 
 #include "core/frame/csp/CSPDirective.h"
 #include "platform/network/ContentSecurityPolicyParsers.h"
 #include "wtf/HashSet.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class ContentSecurityPolicy;
 
-class MediaListDirective final : public CSPDirective {
+class CORE_EXPORT MediaListDirective final : public CSPDirective {
   WTF_MAKE_NONCOPYABLE(MediaListDirective);
 
  public:
   MediaListDirective(const String& name,
                      const String& value,
                      ContentSecurityPolicy*);
   bool allows(const String& type);
 
+  // The algorothm is described more extensively here:
+  // https://w3c.github.io/webappsec-csp/embedded/#subsume-policy.
+  bool subsumes(const std::vector<MediaListDirective*>& other);
+
  private:
+  FRIEND_TEST_ALL_PREFIXES(MediaListDirectiveTest, GetIntersect);
+  FRIEND_TEST_ALL_PREFIXES(MediaListDirectiveTest, Subsumes);
+
   void parse(const UChar* begin, const UChar* end);
 
+  // The algorothm is described more extensively here:
+  // https://w3c.github.io/webappsec-csp/embedded/#subsume-policy.
+  HashSet<String> getIntersect(const HashSet<String>& other);
+
   HashSet<String> m_pluginTypes;
 };
 
 }  // namespace blink
 
 #endif