Add an experimental permissions API for extensions.

chrome/common/extensions/url_pattern_set.h

Index: chrome/common/extensions/url_pattern_set.h
diff --git a/chrome/common/extensions/url_pattern_set.h b/chrome/common/extensions/url_pattern_set.h
index 1848e746247f042223c9a4cfa2d8fdedec1ca1c4..d26321c522b9d1125c2624a3a8c20a9e235853eb 100644
--- a/chrome/common/extensions/url_pattern_set.h
+++ b/chrome/common/extensions/url_pattern_set.h
@@ -18,6 +18,17 @@ class URLPatternSet {
   typedef std::set<URLPattern>::const_iterator const_iterator;
   typedef std::set<URLPattern>::iterator iterator;
 
+  // Clears |out| and populates the set with |set1| - |set2|.
+  static void CreateDifference(const URLPatternSet& set1,
+                               const URLPatternSet& set2,
+                               URLPatternSet* out);
+
+  // Clears |out| and populates the set with the intersection of |set1|
+  // and |set2|.
+  static void CreateIntersection(const URLPatternSet& set1,
+                                 const URLPatternSet& set2,
+                                 URLPatternSet* out);
+
   // Clears |out| and populates the set with the union of |set1| and |set2|.
   static void CreateUnion(const URLPatternSet& set1,
                           const URLPatternSet& set2,
@@ -39,6 +50,9 @@ class URLPatternSet {
   void AddPattern(const URLPattern& pattern);
   void ClearPatterns();
 
+  // Returns true if the permission |set| is a subset of this.
+  bool Contains(const URLPatternSet& set) const;
+
   // Test if the extent contains a URL.
   bool MatchesURL(const GURL& url) const;