Cleanup: make ExtensionRequestSender manage its IPC responses directly, rather

chrome/renderer/extensions/extension_request_sender.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_RENDERER_EXTENSIONS_EXTENSION_REQUEST_SENDER_H_
 #define CHROME_RENDERER_EXTENSIONS_EXTENSION_REQUEST_SENDER_H_
 #pragma once
 
 #include <string>
 #include <map>
 
+#include "base/compiler_specific.h"
 #include "base/memory/linked_ptr.h"
+#include "base/scoped_observer.h"
+#include "content/public/renderer/render_process_observer.h"
 #include "v8/include/v8.h"
 
 class ChromeV8ContextSet;
 class ExtensionDispatcher;
 
 namespace base {
 class ListValue;
 }
 
+namespace content {
+class RenderThread;
+}
+
 struct PendingRequest;
 
 // Responsible for sending requests for named extension API functions to the
 // extension host and routing the responses back to the caller.
-class ExtensionRequestSender {
+class ExtensionRequestSender : content::RenderProcessObserver {
  public:
   explicit ExtensionRequestSender(ExtensionDispatcher* extension_dispatcher,
                                   ChromeV8ContextSet* context_set);
-  ~ExtensionRequestSender();
+  virtual ~ExtensionRequestSender();
 
   // Makes a call to the API function |name| that is to be handled by the
-  // extension host. The response to this request will be received in
-  // HandleResponse().
-  // TODO(koz): Remove |request_id| and generate that internally.
-  void StartRequest(const std::string& name,
-                    int request_id,
-                    bool has_callback,
-                    bool for_io_thread,
-                    base::ListValue* value_args);
-
-  // Handles responses from the extension host to calls made by StartRequest().
-  void HandleResponse(int request_id,
-                      bool success,
-                      const base::ListValue& response,
-                      const std::string& error);
-
+  // extension host.
+  // Returns the request ID of the request, or -1 if no request was made.
+  int StartRequest(const std::string& name,
+                   bool has_callback,
+                   bool for_io_thread,
+                   base::ListValue* value_args);
 
  private:
-  typedef std::map<int, linked_ptr<PendingRequest> > PendingRequestMap;
+  // content::RenderProcessObserver implementation.
+  virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  void OnExtensionResponse(int request_id,
+                           bool success,
+                           const base::ListValue& response,
+                           const std::string& error);
 
   void InsertRequest(int request_id, PendingRequest* pending_request);
   linked_ptr<PendingRequest> RemoveRequest(int request_id);
 
+  // Owner (weak reference).
   ExtensionDispatcher* extension_dispatcher_;
+
+  // V8 contexts (weak reference).
+  ChromeV8ContextSet* context_set_;
+
+  // Scoped observer to RenderProcessHost.
+  ScopedObserver<content::RenderThread, content::RenderProcessObserver>
+      scoped_observer_;
+
+  // The next request ID.
+  int next_request_id_;
+
+  // Pending requests.
+  typedef std::map<int, linked_ptr<PendingRequest> > PendingRequestMap;
   PendingRequestMap pending_requests_;
-  ChromeV8ContextSet* context_set_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionRequestSender);
 };
 
 #endif  // CHROME_RENDERER_EXTENSIONS_EXTENSION_REQUEST_SENDER_H_