Tweak ifdefs for MessageLoopForUI::Add/RemoveObserver

This is necessitated by our building of base for tools. In particular
if I set OS_ANDROID and USE_AURA then the host is built with OS_LINUX
and USE_AURA, but none of the other flags we normally set if USE_AURA
is set for OS_LINUX.

And yes, I really need to spend time and refactor messageloop. It is
such a mess of ifdefs right now.

BUG=none
TEST=none
R=darin@chromium.org

Review URL: https://codereview.chromium.org/129873003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244386 0039d316-1c4b-4281-b951-d872f2087c98


CrOS-Libchrome-Original-Commit: 0b41c523c5d8eb77c5d3a7cbcfab0068fde55192
diff --git a/base/message_loop/message_loop.cc b/base/message_loop/message_loop.cc
index 712fcfa..bbf7cd3 100644
--- a/base/message_loop/message_loop.cc
+++ b/base/message_loop/message_loop.cc
@@ -665,7 +665,8 @@
 }
 #endif
 
-#if !defined(OS_MACOSX) && !defined(OS_NACL) && !defined(OS_ANDROID)
+#if !defined(OS_NACL) && (defined(TOOLKIT_GTK) || defined(USE_OZONE) || \
+                          defined(OS_WIN) || defined(USE_X11))
 void MessageLoopForUI::AddObserver(Observer* observer) {
   pump_ui()->AddObserver(observer);
 }
@@ -673,7 +674,6 @@
 void MessageLoopForUI::RemoveObserver(Observer* observer) {
   pump_ui()->RemoveObserver(observer);
 }
-
 #endif  //  !defined(OS_MACOSX) && !defined(OS_NACL) && !defined(OS_ANDROID)
 
 //------------------------------------------------------------------------------