Cleanup: Remove unneeded extension_messages.h usage and ifdef out some extensions code usage when e…

chrome/browser/sessions/session_tab_helper.cc

Index: chrome/browser/sessions/session_tab_helper.cc
diff --git a/chrome/browser/sessions/session_tab_helper.cc b/chrome/browser/sessions/session_tab_helper.cc
index c4c0e4e9983dff53d77b5d211f5b65d691f6de12..467ed22d5f67c0beb13f6c5c6343a144e6c395ec 100644
--- a/chrome/browser/sessions/session_tab_helper.cc
+++ b/chrome/browser/sessions/session_tab_helper.cc
@@ -11,7 +11,10 @@
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
+
+#if defined(ENABLE_EXTENSIONS)
 #include "extensions/common/extension_messages.h"
+#endif
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(SessionTabHelper);
 
@@ -25,11 +28,13 @@ SessionTabHelper::~SessionTabHelper() {
 void SessionTabHelper::SetWindowID(const SessionID& id) {
   window_id_ = id;
 
+#if defined(ENABLE_EXTENSIONS)
   // Extension code in the renderer holds the ID of the window that hosts it.
   // Notify it that the window ID changed.
   web_contents()->GetRenderViewHost()->Send(
           new ExtensionMsg_UpdateBrowserWindowId(
           web_contents()->GetRenderViewHost()->GetRoutingID(), id.id()));
+#endif
 }
 
 // static
@@ -47,12 +52,14 @@ SessionID::id_type SessionTabHelper::IdForWindowContainingTab(
   return session_tab_helper ? session_tab_helper->window_id().id() : -1;
 }
 
+#if defined(ENABLE_EXTENSIONS)
 void SessionTabHelper::RenderViewCreated(
     content::RenderViewHost* render_view_host) {
   render_view_host->Send(
       new ExtensionMsg_UpdateBrowserWindowId(render_view_host->GetRoutingID(),
                                              window_id_.id()));
 }
+#endif
 
 void SessionTabHelper::UserAgentOverrideSet(const std::string& user_agent) {
 #if defined(ENABLE_SESSION_SERVICE)