[Extensions] Clean up the handling of ExtensionHostMsg_Request

extensions/browser/guest_view/app_view/app_view_guest.cc

Index: extensions/browser/guest_view/app_view/app_view_guest.cc
diff --git a/extensions/browser/guest_view/app_view/app_view_guest.cc b/extensions/browser/guest_view/app_view/app_view_guest.cc
index 9c157d0406f694458235df1fbbd91fad21a978fa..108b9b3e2c0092de4954d070dff88d7ec48d277f 100644
--- a/extensions/browser/guest_view/app_view/app_view_guest.cc
+++ b/extensions/browser/guest_view/app_view/app_view_guest.cc
@@ -104,23 +104,6 @@ AppViewGuest::AppViewGuest(content::WebContents* owner_web_contents)
 AppViewGuest::~AppViewGuest() {
 }
 
-WindowController* AppViewGuest::GetExtensionWindowController() const {
-  return nullptr;
-}
-
-content::WebContents* AppViewGuest::GetAssociatedWebContents() const {
-  return web_contents();
-}
-
-bool AppViewGuest::OnMessageReceived(const IPC::Message& message) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(AppViewGuest, message)
-    IPC_MESSAGE_HANDLER(ExtensionHostMsg_Request, OnRequest)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
-}
-
 bool AppViewGuest::HandleContextMenu(const content::ContextMenuParams& params) {
   if (app_view_guest_delegate_) {
     return app_view_guest_delegate_->HandleContextMenu(web_contents(), params);
@@ -226,8 +209,7 @@ void AppViewGuest::CreateWebContents(
 }
 
 void AppViewGuest::DidInitialize(const base::DictionaryValue& create_params) {
-  extension_function_dispatcher_.reset(
-      new ExtensionFunctionDispatcher(browser_context(), this));
+  ExtensionsAPIClient::Get()->AttachWebContentsHelpers(web_contents());
 
   if (!url_.is_valid())
     return;
@@ -244,11 +226,6 @@ int AppViewGuest::GetTaskPrefix() const {
   return IDS_EXTENSION_TASK_MANAGER_APPVIEW_TAG_PREFIX;
 }
 
-void AppViewGuest::OnRequest(const ExtensionHostMsg_Request_Params& params) {
-  extension_function_dispatcher_->Dispatch(params,
-                                           web_contents()->GetRenderViewHost());
-}
-
 void AppViewGuest::CompleteCreateWebContents(
     const GURL& url,
     const Extension* guest_extension,