Rework some UserScriptLoader logic in preparation to removing UserScript copy.

extensions/common/user_script.h

 // Copyright 2013 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_COMMON_USER_SCRIPT_H_
 #define EXTENSIONS_COMMON_USER_SCRIPT_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 299 matching lines @@
   bool match_all_frames_;
 
   // Whether the user script should run in about:blank and about:srcdoc as well.
   // Defaults to false.
   bool match_about_blank_;
 
   // True if the script should be injected into an incognito tab.
   bool incognito_enabled_;
 };
 
+// Information we need while removing scripts from a UserScriptLoader.
+struct UserScriptIDPair {
+  UserScriptIDPair(int id, const HostID& host_id);
+  UserScriptIDPair(int id);
+
+  int id;
+  HostID host_id;
+};
+
 // For storing UserScripts with unique IDs in sets.
 bool operator<(const UserScript& script1, const UserScript& script2);
 
+bool operator<(const UserScriptIDPair& a, const UserScriptIDPair& b);
+
 typedef std::vector<UserScript> UserScriptList;
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_USER_SCRIPT_H_