Introduce DeclarativeUserScriptManager.

chrome/browser/extensions/declarative_user_script_manager.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 CHROME_BROWSER_EXTENSIONS_DECLARATIVE_USER_SCRIPT_MANAGER_H_
+#define CHROME_BROWSER_EXTENSIONS_DECLARATIVE_USER_SCRIPT_MANAGER_H_
+

[Devlin, 2014/12/12 18:08:07]

#include <map>

[Xi Han, 2014/12/12 19:47:24]

Done.

+#include "base/macros.h"
+#include "base/memory/linked_ptr.h"
+#include "extensions/common/extension.h"
+
+class Profile;
+
+namespace extensions {
+
+class DeclarativeUserScriptMaster;
+
+class DeclarativeUserScriptManager {

[Devlin, 2014/12/12 18:08:07]

Class comments needed.

[Xi Han, 2014/12/12 19:47:24]

Done.

+ public:
+  explicit DeclarativeUserScriptManager(Profile* profile);
+  ~DeclarativeUserScriptManager();
+
+  // Get the user script master for declarative scripts, if any.

[Devlin, 2014/12/12 18:08:07]

This "if any" is misleading - it implies this could return null.
Instead, how about "Get the user script master for declarative scripts; if one
does not exist, it will be created."?

[Xi Han, 2014/12/12 19:47:24]

Good catch, updated:)

+  DeclarativeUserScriptMaster* GetDeclarativeUserScriptMasterByID(
+      const ExtensionId& extension_id);

[Devlin, 2014/12/12 18:08:07]

I'm slightly confused on passing in an ExtensionId here - isn't one of the goals
to make this accept an abstract "id"?  (In practice, this change will probably
just be changing "ExtensionId" to "std::string", but from a conceptual
standpoint, it makes a bigger difference).

[Xi Han, 2014/12/12 19:47:24]

I planed this CL only moves code around, but I can do some renaming as well to
improve readability.

+
+ private:
+  Profile* profile_;
+
+  typedef std::map<ExtensionId, linked_ptr<DeclarativeUserScriptMaster>>

[Devlin, 2014/12/12 18:08:07]

nit: typedefs before class members.

[Devlin, 2014/12/12 18:08:07]

nit: we now prefer C++ 11 style for these:
using UserScriptMasterMap = std::map<ExtensionId,
linked_ptr<DeclarativeUserScriptMaster>>;

[Xi Han, 2014/12/12 19:47:24]

Thanks for pointing it out:)

[Xi Han, 2014/12/12 19:47:24]

Moved.

+      UserScriptMasterMap;
+
+  // Shared memory region manager for programmatically declared scripts.

[Devlin, 2014/12/12 18:08:07]

I'm not sure what the "Shared memory region" refers to for this...?  (If it's
not referring to base::SharedMemory, probably best to rephrase, since the Script
Injection System also uses that shared memory.)

[Xi Han, 2014/12/12 19:47:24]

I think it is refer to base::SharedMemory, since the UserScriptLoader within
each master object has a pointer to the base::sharedMemory. Updated the
description to avoid confusion.

+  // Managers are instantiated the first time the declarative

[Devlin, 2014/12/12 18:08:07]

nit: s/the first time..../lazily.

[Xi Han, 2014/12/12 19:47:24]

Done.

+  // API is used by an extension to request content scripts.
+  UserScriptMasterMap declarative_user_script_masters_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeclarativeUserScriptManager);
+};
+
+}  // extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_DECLARATIVE_USER_SCRIPT_MANAGER_H_