Headers cleanup in chrome/common

chrome/common/ipc_sync_channel.h

Index: chrome/common/ipc_sync_channel.h
diff --git a/chrome/common/ipc_sync_channel.h b/chrome/common/ipc_sync_channel.h
index 1b192f6cf53ba3278ef99420233914333a8e1a2c..2208a67982ab16f5cdce5aed721265a0459669cb 100644
--- a/chrome/common/ipc_sync_channel.h
+++ b/chrome/common/ipc_sync_channel.h
@@ -7,14 +7,17 @@
 
 #include <string>
 #include <deque>
+
 #include "base/basictypes.h"
 #include "base/lock.h"
 #include "base/ref_counted.h"
-#include "base/scoped_handle.h"
-#include "base/waitable_event.h"
 #include "base/waitable_event_watcher.h"
 #include "chrome/common/ipc_channel_proxy.h"
 
+namespace base {
+class WaitableEvent;
+};
+
 namespace IPC {
 
 class SyncMessage;