Introduce HostID and de-couple Extensions from "script injection System" [browser side]

chrome/browser/extensions/api/declarative_content/content_action.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 CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_CONTENT_CONTENT_ACTION_H_
 #define CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_CONTENT_CONTENT_ACTION_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 49 matching lines @@
                       ApplyInfo* apply_info) const = 0;
 
   // Factory method that instantiates a concrete ContentAction
   // implementation according to |json_action|, the representation of the
   // ContentAction as received from the extension API.
   // Sets |error| and returns NULL in case of a semantic error that cannot
   // be caught by schema validation. Sets |bad_message| and returns NULL
   // in case the input is syntactically unexpected.
   static scoped_refptr<ContentAction> Create(
       content::BrowserContext* browser_context,
+      const HostID& host_id,
       const Extension* extension,

[Devlin, 2015/01/26 20:12:08]

We're already passing in an extension to all of these different methods.  Do we
really need to pass in a host id, rather than having the action construct a host
id from the extension object?

[Xi Han, 2015/01/26 23:27:53]

Yes, because for webUI, we want to pass in the id of webUI (e.g.,  a string of
its url). This id can only be created when <webview> is registering the
declarative content rules.  I think the confusion here is caused by creating a
HostID from ChromeContentRulesRegistry, in fact the HostID should be created in
declarative_api.cc and plumbed to here. The rule registry part will be updated
in a following patch, since de-couple extension is also required.

       const base::Value& json_action,
       std::string* error,
       bool* bad_message);
 
   // Shared procedure for resetting error state within factories.
   static void ResetErrorData(std::string* error, bool* bad_message) {
     *error = "";
     *bad_message = false;
   }
 
   // Shared procedure for validating JSON data.
   static bool Validate(const base::Value& json_action,
                        std::string* error,
                        bool* bad_message,
                        const base::DictionaryValue** action_dict,
                        std::string* instance_type);
 
  protected:
   friend class base::RefCounted<ContentAction>;
   virtual ~ContentAction();
 };
 
 // Action that injects a content script.
 class RequestContentScript : public ContentAction {
  public:
   struct ScriptData;
 
   RequestContentScript(content::BrowserContext* browser_context,
+                       const HostID& host_id,
                        const Extension* extension,
                        const ScriptData& script_data);
   RequestContentScript(DeclarativeUserScriptMaster* master,
+                       const HostID& host_id,
                        const Extension* extension,
                        const ScriptData& script_data);
 
   static scoped_refptr<ContentAction> Create(
       content::BrowserContext* browser_context,
+      const HostID& host_id,
       const Extension* extension,
       const base::DictionaryValue* dict,
       std::string* error,
       bool* bad_message);
 
   static scoped_refptr<ContentAction> CreateForTest(
       DeclarativeUserScriptMaster* master,
+      const HostID& host_id,
       const Extension* extension,
       const base::Value& json_action,
       std::string* error,
       bool* bad_message);
 
   static bool InitScriptData(const base::DictionaryValue* dict,
                              std::string* error,
                              bool* bad_message,
                              ScriptData* script_data);
 
   // Implementation of ContentAction:
   Type GetType() const override;
 
   void Apply(const std::string& extension_id,
              const base::Time& extension_install_time,
              ApplyInfo* apply_info) const override;
 
   void Reapply(const std::string& extension_id,
                const base::Time& extension_install_time,
                ApplyInfo* apply_info) const override;
 
   void Revert(const std::string& extension_id,
               const base::Time& extension_install_time,
               ApplyInfo* apply_info) const override;
 
  private:
-  void InitScript(const Extension* extension, const ScriptData& script_data);
+  void InitScript(const HostID& host_id,
+                  const Extension* extension,
+                  const ScriptData& script_data);
 
   void AddScript() {
     DCHECK(master_);
     master_->AddScript(script_);
   }
 
   ~RequestContentScript() override;
 
   void InstructRenderProcessToInject(content::WebContents* contents,
                                      const std::string& extension_id) const;
 
   UserScript script_;
   DeclarativeUserScriptMaster* master_;
 
   DISALLOW_COPY_AND_ASSIGN(RequestContentScript);
 };
 
 typedef DeclarativeActionSet<ContentAction> ContentActionSet;
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_CONTENT_CONTENT_ACTION_H_