Build sync engine as part of the browser build

chrome/browser/sync/engine/syncer_thread.cc

Index: chrome/browser/sync/engine/syncer_thread.cc
===================================================================
--- chrome/browser/sync/engine/syncer_thread.cc	(revision 26149)
+++ chrome/browser/sync/engine/syncer_thread.cc	(working copy)
@@ -4,6 +4,8 @@
 
 #include "chrome/browser/sync/engine/syncer_thread.h"
 
+#include "build/build_config.h"
+
 #ifdef OS_MACOSX
 #include <CoreFoundation/CFNumber.h>
 #include <IOKit/IOTypes.h>
@@ -34,7 +36,7 @@
 // Returns the amount of time since the user last interacted with the computer,
 // in milliseconds
 int UserIdleTime() {
-#ifdef OS_WINDOWS
+#ifdef OS_WIN
   LASTINPUTINFO last_input_info;
   last_input_info.cbSize = sizeof(LASTINPUTINFO);