Revert 99810 - Get the rest of the chrome target to build (but not link) with USE_AURA.

ipc/ipc_message_utils.h

Index: ipc/ipc_message_utils.h
===================================================================
--- ipc/ipc_message_utils.h	(revision 99812)
+++ ipc/ipc_message_utils.h	(working copy)
@@ -20,10 +20,6 @@
 #include "ipc/ipc_param_traits.h"
 #include "ipc/ipc_sync_message.h"
 
-#if defined(USE_AURA)
-#include "ui/gfx/native_widget_types.h"
-#endif
-
 #if defined(COMPILER_GCC)
 // GCC "helpfully" tries to inline template methods in release mode. Except we
 // want the majority of the template junk being expanded once in the
@@ -663,13 +659,9 @@
   }
 };
 
-#if defined(USE_AURA)
-// TODO(beng): Figure out why this is needed, fix that issue and remove
-//             this. Brett and I were unable to figure out why, but he
-//             thought this should be harmless.
 template <>
-struct ParamTraits<gfx::PluginWindowHandle> {
-  typedef gfx::PluginWindowHandle param_type;
+struct ParamTraits<HCURSOR> {
+  typedef HCURSOR param_type;
   static void Write(Message* m, const param_type& p) {
     m->WriteUInt32(reinterpret_cast<uint32>(p));
   }
@@ -681,7 +673,6 @@
     l->append(StringPrintf("0x%X", p));
   }
 };
-#endif
 
 template <>
 struct ParamTraits<HACCEL> {