Rework some UserScriptLoader logic in preparation to removing UserScript copy.

extensions/browser/user_script_loader.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 EXTENSIONS_BROWSER_USER_SCRIPT_LOADER_H_
 #define EXTENSIONS_BROWSER_USER_SCRIPT_LOADER_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 40 matching lines @@
 
   // Parses the includes out of |script| and returns them in |includes|.
   static bool ParseMetadataHeader(const base::StringPiece& script_text,
                                   UserScript* script);
 
   UserScriptLoader(content::BrowserContext* browser_context,
                    const HostID& host_id);
   ~UserScriptLoader() override;
 
   // Add |scripts| to the set of scripts managed by this loader.
-  void AddScripts(const std::set<UserScript>& scripts);
+  void AddScripts(const UserScriptList& scripts);
 
   // Add |scripts| to the set of scripts managed by this loader.
   // The fetch of the content of the script starts URL request
   // to the associated render specified by
   // |render_process_id, render_view_id|.
   // TODO(hanxi): The renderer information doesn't really belong in this base
   // class, but it's not an easy fix.
-  virtual void AddScripts(const std::set<UserScript>& scripts,
+  virtual void AddScripts(const UserScriptList& scripts,
                           int render_process_id,
                           int render_view_id);
 
-  // Remove |scripts| from the set of scripts managed by this loader.
-  void RemoveScripts(const std::set<UserScript>& scripts);
+  // Removes scripts with ids specified in |scripts| from the set of scripts
+  // managed by this loader.
+  // TODO(lazyboy): Likely we can make |scripts| a std::vector, but
+  // WebViewContentScriptManager makes this non-trivial.
+  void RemoveScripts(const std::set<UserScriptIDPair>& scripts);
 
   // Clears the set of scripts managed by this loader.
   void ClearScripts();
 
   // Initiates procedure to start loading scripts on the file thread.
   void StartLoad();
 
   // Returns true if we have any scripts ready.
   bool scripts_ready() const { return shared_memory_.get() != NULL; }
 
@@ skipping 40 matching lines @@
   // Sends the renderer process a new set of user scripts. If
   // |changed_hosts| is not empty, this signals that only the scripts from
   // those hosts should be updated. Otherwise, all hosts will be
   // updated.
   void SendUpdate(content::RenderProcessHost* process,
                   base::SharedMemory* shared_memory,
                   const std::set<HostID>& changed_hosts);
 
   bool is_loading() const {
     // Ownership of |user_scripts_| is passed to the file thread when loading.
-    return user_scripts_.get() == NULL;
+    return user_scripts_.get() == nullptr;
   }
 
   // Manages our notification registrations.
   content::NotificationRegistrar registrar_;
 
   // Contains the scripts that were found the last time scripts were updated.
   std::unique_ptr<base::SharedMemory> shared_memory_;
 
   // List of scripts from currently-installed extensions we should load.
   std::unique_ptr<UserScriptList> user_scripts_;
 
-  // The mutually-exclusive sets of scripts that were added or removed since the
-  // last script load.
-  std::set<UserScript> added_scripts_;
-  std::set<UserScript> removed_scripts_;
+  // The mutually-exclusive information about sets of scripts that were added or
+  // removed since the last script load. These maps are keyed by script's id.

[Devlin, 2016/08/11 01:09:27]

Nit: "keyed by script ids" maybe?

[lazyboy, 2016/08/11 01:51:06]

Done.

+  // Note that we only need HostID information for removal.
+  std::map<int, UserScript> added_scripts_map_;
+  std::set<UserScriptIDPair> removed_script_hosts_;
 
   // Indicates whether the the collection of scripts should be cleared before
   // additions and removals on the next script load.
   bool clear_scripts_;
 
   // The IDs of the extensions which changed in the last update sent to the
   // renderer.
   std::set<HostID> changed_hosts_;
 
   // If the initial set of hosts has finished loading.
@@ skipping 15 matching lines @@
   base::ObserverList<Observer> observers_;
 
   base::WeakPtrFactory<UserScriptLoader> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(UserScriptLoader);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_USER_SCRIPT_LOADER_H_