[Extensions] Clean up the handling of ExtensionHostMsg_Request

extensions/browser/extension_host.cc

Index: extensions/browser/extension_host.cc
diff --git a/extensions/browser/extension_host.cc b/extensions/browser/extension_host.cc
index 124a8fd2ddf3c4ca1502ec2369beb1676c774073..c3e041ae9bf92e005425f71520c98a92bcd0d5b5 100644
--- a/extensions/browser/extension_host.cc
+++ b/extensions/browser/extension_host.cc
@@ -27,6 +27,7 @@
 #include "extensions/browser/extension_host_queue.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
+#include "extensions/browser/extension_web_contents_observer.h"
 #include "extensions/browser/extensions_browser_client.h"
 #include "extensions/browser/load_monitoring_extension_host_queue.h"
 #include "extensions/browser/notification_types.h"
@@ -62,7 +63,6 @@ ExtensionHost::ExtensionHost(const Extension* extension,
       has_loaded_once_(false),
       document_element_available_(false),
       initial_url_(url),
-      extension_function_dispatcher_(browser_context_, this),
       extension_host_type_(host_type) {
   // Not used for panels, see PanelHost.
   DCHECK(host_type == VIEW_TYPE_EXTENSION_BACKGROUND_PAGE ||
@@ -82,6 +82,9 @@ ExtensionHost::ExtensionHost(const Extension* extension,
 
   // Set up web contents observers and pref observers.
   delegate_->OnExtensionHostCreated(host_contents());
+
+  ExtensionWebContentsObserver::GetForWebContents(host_contents())->
+      dispatcher()->set_delegate(this);
 }
 
 ExtensionHost::~ExtensionHost() {
@@ -321,7 +324,6 @@ void ExtensionHost::CloseContents(WebContents* contents) {
 bool ExtensionHost::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(ExtensionHost, message)
-    IPC_MESSAGE_HANDLER(ExtensionHostMsg_Request, OnRequest)
     IPC_MESSAGE_HANDLER(ExtensionHostMsg_EventAck, OnEventAck)
     IPC_MESSAGE_HANDLER(ExtensionHostMsg_IncrementLazyKeepaliveCount,
                         OnIncrementLazyKeepaliveCount)
@@ -332,10 +334,6 @@ bool ExtensionHost::OnMessageReceived(const IPC::Message& message) {
   return handled;
 }
 
-void ExtensionHost::OnRequest(const ExtensionHostMsg_Request_Params& params) {
-  extension_function_dispatcher_.Dispatch(params, render_view_host());
-}
-
 void ExtensionHost::OnEventAck(int event_id) {
   EventRouter* router = EventRouter::Get(browser_context_);
   if (router)