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);
 
+  // Gets the associated injection host. If the host is an extension, we check
+  // whether the extension exists first; and if the extension is gone, will
+  // return a nullptr.
+  const InjectionHost* GetInjectionHost();
+
   // 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_; }
 
  private:
   // Send a message to the browser requesting permission to execute.
   void RequestPermission();
 
   // Injects the script, optionally populating |scripts_run_info|.
   void Inject(const InjectionHost* injection_host,
               ScriptsRunInfo* scripts_run_info);
 
   // Inject any JS scripts into the |frame|, optionally populating
   // |execution_results|.
   void InjectJs(const InjectionHost* injection_host,
                 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_