Refactoring: de-couple Extensions from "script injection System" [render side]:3

extensions/renderer/script_injection.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_RENDERER_SCRIPT_INJECTION_H_
 #define EXTENSIONS_RENDERER_SCRIPT_INJECTION_H_
 
 #include "base/basictypes.h"
 #include "base/macros.h"
 #include "extensions/common/user_script.h"
+#include "extensions/renderer/injection_host.h"
 #include "extensions/renderer/script_injector.h"
 
-class InjectionHost;
 struct HostID;
 
 namespace blink {
 class WebLocalFrame;
 }
 
 namespace extensions {
 struct ScriptsRunInfo;
 
 // A script wrapper which is aware of whether or not it is allowed to execute,
 // and contains the implementation to do so.
 class ScriptInjection {
  public:
   // Return the id of the injection host associated with the given world.
   static std::string GetHostIdForIsolatedWorld(int world_id);
 
   // Remove the isolated world associated with the given injection host.
   static void RemoveIsolatedWorld(const std::string& host_id);
 
   ScriptInjection(
       scoped_ptr<ScriptInjector> injector,
       blink::WebLocalFrame* web_frame,
-      const HostID& host_id,
+      scoped_ptr<const InjectionHost> injection_host,
       const UserScript::ConsumerInstanceType& consumer_instance_type,
       UserScript::RunLocation run_location,
       int tab_id);
   ~ScriptInjection();
 
   // Try to inject the script at the |current_location|. This returns true if
   // the script has either injected or will never inject (i.e., if the object
   // is done), and false if injection is delayed (either for permission purposes
   // or because |current_location| is not the designated |run_location_|).
-  // NOTE: |injection_host| may be NULL, if the injection_host is removed!
   bool TryToInject(UserScript::RunLocation current_location,
-                   const InjectionHost* injection_host,
                    ScriptsRunInfo* scripts_run_info);
 
   // Called when permission for the given injection has been granted.
   // Returns true if the injection ran.
-  bool OnPermissionGranted(const InjectionHost* injection_host,
-                           ScriptsRunInfo* scripts_run_info);
+  bool OnPermissionGranted(ScriptsRunInfo* scripts_run_info);
 
   // Accessors.
   blink::WebLocalFrame* web_frame() const { return web_frame_; }
-  const HostID& host_id() const { return host_id_; }
+  const HostID& host_id() const { return injection_host_->id(); }
   int64 request_id() const { return request_id_; }
+  void set_injection_host(InjectionHost* host) {

[Devlin, 2015/02/20 22:39:13]

two things:
- if this would actually reset the host to a new one, we should probably pass a
scoped_ptr, because it enforces the ownership scheme.
- it doesn't look like we ever use this for anything other than passing nullptr,
so why not just call it "ResetInjectionHost" or "OnHostRemoved" (and move it to
the .cc, please, to avoid the extra import).

[Xi Han, 2015/02/23 16:14:59]

You are right, it makes more sense to have "OnHostRemoved" and just reset the
pointer. Updated.

+    injection_host_.reset(host);
+  }
 
  private:
   // Sends a message to the browser, either that the script injection would
   // like to inject, or to notify the browser that it is currently injecting.
   void SendInjectionMessage(bool request_permission);
 
   // Injects the script, optionally populating |scripts_run_info|.
-  void Inject(const InjectionHost* injection_host,
-              ScriptsRunInfo* scripts_run_info);
+  void Inject(ScriptsRunInfo* scripts_run_info);
 
   // Inject any JS scripts into the |frame|, optionally populating
   // |execution_results|.
-  void InjectJs(const InjectionHost* injection_host,
-                blink::WebLocalFrame* frame,
+  void InjectJs(blink::WebLocalFrame* frame,
                 base::ListValue* execution_results);
 
   // Inject any CSS source into the |frame|.
   void InjectCss(blink::WebLocalFrame* frame);
 
   // Notify that we will not inject, and mark it as acknowledged.
   void NotifyWillNotInject(ScriptInjector::InjectFailureReason reason);
 
   // The injector for this injection.
   scoped_ptr<ScriptInjector> injector_;
 
   // The (main) WebFrame into which this should inject the script.
   blink::WebLocalFrame* web_frame_;
 
-  // The id of the associated injection_host.
-  HostID host_id_;
+  // The associated injection host.
+  scoped_ptr<const InjectionHost> injection_host_;
 
   // The type of the instance on which the host will inject the script.
   UserScript::ConsumerInstanceType consumer_instance_type_;
 
   // The location in the document load at which we inject the script.
   UserScript::RunLocation run_location_;
 
   // The tab id associated with the frame.
   int tab_id_;
 
   // This injection's request id. This will be -1 unless the injection is
   // currently waiting on permission.
   int64 request_id_;
 
   // Whether or not the injection is complete, either via injecting the script
   // or because it will never complete.
   bool complete_;
 
   DISALLOW_COPY_AND_ASSIGN(ScriptInjection);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_SCRIPT_INJECTION_H_