Part 1.1: Is policy list subsumed under subsuming policy?

third_party/WebKit/Source/core/frame/csp/CSPSource.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 CSPSource_h
 #define CSPSource_h
 
 #include "core/CoreExport.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "platform/heap/Handle.h"
@@ skipping 13 matching lines @@
   CSPSource(ContentSecurityPolicy*,
             const String& scheme,
             const String& host,
             int port,
             const String& path,
             WildcardDisposition hostWildcard,
             WildcardDisposition portWildcard);
   bool matches(const KURL&,
                ResourceRequest::RedirectStatus =
                    ResourceRequest::RedirectStatus::NoRedirect) const;
+  // Check whether this CSPSource is subsumed under a given CSPSource for a
+  // subsumption algorithm described here:
+  // https://w3c.github.io/webappsec-csp/embedded/#subsume-policy
+  bool isSubsumedBy(CSPSource*);
+  // Retrieve the most common information from the two CSPSources if isSimilar
+  // is true for the two. Otherwise, return nullptr.
+  CSPSource* getCommon(CSPSource*);
 
   DECLARE_TRACE();
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(CSPSourceTest, IsSimilar);
+
   bool schemeMatches(const String&) const;
   bool hostMatches(const String&) const;
   bool pathMatches(const String&) const;
   bool portMatches(int, const String&) const;
   bool isSchemeOnly() const;
+  bool isPathEmptyOrSlashOnly() const;
+  // Check if either one of the two matches the scheme, host, port, path of the
+  // other. More detailed explanation here:
+  // https://docs.google.com/document/d/1xwTxpB_sWYaTrOBJEPSXtfWKO4M2k9Xya7o0zcd6Dec/edit#heading=h.9efhej5pg0hj

[Mike West, 2016/11/04 09:48:10]

1. This needs to be a publicly accessible link. `google.com` docs can't be made
public.
2. I'd prefer to link to the spec; can we upstream your algorithm to that
document?

+  bool isSimilar(CSPSource* other);
+
+  bool isWildcardsSubsumedBy(CSPSource* other);
+  bool isSchemeSubsumedBy(CSPSource* other);
+  bool isPortSubsumedBy(CSPSource* other);
+  bool isPathSubsumedBy(CSPSource* other);
 
   Member<ContentSecurityPolicy> m_policy;
   String m_scheme;
   String m_host;
   int m_port;
   String m_path;
 
   WildcardDisposition m_hostWildcard;
   WildcardDisposition m_portWildcard;
 };
 
 }  // namespace blink
 
 #endif