Split ExtensionMessageFilter up into a UI thread part and an IO thread part.

extensions/browser/api/web_request/web_request_api.cc

Index: extensions/browser/api/web_request/web_request_api.cc
diff --git a/extensions/browser/api/web_request/web_request_api.cc b/extensions/browser/api/web_request/web_request_api.cc
index 87da356ebce5602f6072deb5f7d75d62d8983b65..c7fab7c23d64c1b77beae1d219a8c7498f434abf 100644
--- a/extensions/browser/api/web_request/web_request_api.cc
+++ b/extensions/browser/api/web_request/web_request_api.cc
@@ -34,7 +34,6 @@
 #include "extensions/browser/api/web_request/web_request_event_router_delegate.h"
 #include "extensions/browser/api/web_request/web_request_time_tracker.h"
 #include "extensions/browser/event_router.h"
-#include "extensions/browser/extension_message_filter.h"
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
@@ -42,6 +41,7 @@
 #include "extensions/browser/guest_view/web_view/web_view_constants.h"
 #include "extensions/browser/guest_view/web_view/web_view_renderer_state.h"
 #include "extensions/browser/info_map.h"
+#include "extensions/browser/io_thread_extension_message_filter.h"
 #include "extensions/browser/runtime_data.h"
 #include "extensions/browser/warning_service.h"
 #include "extensions/browser/warning_set.h"
@@ -2218,7 +2218,7 @@ bool WebRequestInternalAddEventListenerFunction::RunSync() {
   int web_view_instance_id = 0;
   EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(5, &web_view_instance_id));
 
-  base::WeakPtr<extensions::ExtensionMessageFilter> ipc_sender =
+  base::WeakPtr<extensions::IOThreadExtensionMessageFilter> ipc_sender =
       ipc_sender_weak();
   int embedder_process_id =
       ipc_sender.get() && web_view_instance_id > 0 ?