Support requesting subsets of host permissions using the permissions API.

extensions/common/url_pattern_set.h

 // Copyright (c) 2012 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 EXTENSIONS_COMMMON_URL_PATTERN_SET_H_
 #define EXTENSIONS_COMMMON_URL_PATTERN_SET_H_
 
 #include <set>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 50 matching lines @@
 
   // Adds a pattern to the set. Returns true if a new pattern was inserted,
   // false if the pattern was already in the set.
   bool AddPattern(const URLPattern& pattern);
 
   // Adds all patterns from |set| into this.
   void AddPatterns(const URLPatternSet& set);
 
   void ClearPatterns();
 
-  // Returns true if the permission |set| is a subset of this.
+  // Returns true if every URL that matches |set| is matched by this. In other
+  // words, if every pattern in |set| is encompassed by a pattern in this.
   bool Contains(const URLPatternSet& set) const;
 
   // Test if the extent contains a URL.
   bool MatchesURL(const GURL& url) const;
 
   bool MatchesSecurityOrigin(const GURL& origin) const;
 
   // Returns true if there is a single URL that would be in two extents.
   bool OverlapsWith(const URLPatternSet& other) const;
 
   // Converts to and from Value for serialization to preferences.
   scoped_ptr<base::ListValue> ToValue() const;
   bool Populate(const base::ListValue& value,
                 int valid_schemes,
                 bool allow_file_access,
                 std::string* error);
 
   bool Populate(const std::vector<std::string>& patterns,
                 int valid_schemes,
                 bool allow_file_access,
                 std::string* error);
 
  private:
+  // Returns true if any pattern in this set encompasses |pattern|.
+  bool ContainsPattern(const URLPattern& pattern) const;
+
   // The list of URL patterns that comprise the extent.
   std::set<URLPattern> patterns_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMMON_URL_PATTERN_SET_H_