Part 1.1: Is policy list subsumed under subsuming policy?

third_party/WebKit/Source/core/frame/csp/CSPSource.cpp

 // 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.
 
 #include "core/frame/csp/CSPSource.h"
 
 #include "core/frame/UseCounter.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "platform/weborigin/KURL.h"
 #include "platform/weborigin/KnownPorts.h"
@@ skipping 87 matching lines @@
 
   if (!port)
     return isDefaultPortForProtocol(m_port, protocol);
 
   if (!m_port)
     return isDefaultPortForProtocol(port, protocol);
 
   return false;
 }
 
+bool CSPSource::isSubsumingOf(CSPSource* other) {
+  if (!schemeMatches(other->m_scheme))
+    return false;
+
+  if (other->isSchemeOnly() || isSchemeOnly())
+    return isSchemeOnly();
+
+  if ((m_hostWildcard == NoWildcard && other->m_hostWildcard == HasWildcard) ||
+      (m_portWildcard == NoWildcard && other->m_portWildcard == HasWildcard)) {
+    return false;
+  }
+
+  bool hostIsSubsumingOf =
+      (m_host == other->m_host || hostMatches(other->m_host));
+  bool portIsSubsumingOf = (m_portWildcard == HasWildcard) ||
+                           portMatches(other->m_port, other->m_scheme);
+  bool pathIsSubsumingOf = pathMatches(other->m_path);
+  return hostIsSubsumingOf && portIsSubsumingOf && pathIsSubsumingOf;
+}
+
 bool CSPSource::isSchemeOnly() const {
   return m_host.isEmpty();
 }
 
 DEFINE_TRACE(CSPSource) {
   visitor->trace(m_policy);
 }
 
 }  // namespace blink