wm: Update namespace and header define guards.

src/platform/window_manager/motion_event_coalescer.cc

Index: src/platform/window_manager/motion_event_coalescer.cc
diff --git a/src/platform/window_manager/motion_event_coalescer.cc b/src/platform/window_manager/motion_event_coalescer.cc
index ddd8eb0dd0ee52a2984b2328c49eeb7539773318..13142d2c46d59f6b167fa793314aff873a0428ed 100644
--- a/src/platform/window_manager/motion_event_coalescer.cc
+++ b/src/platform/window_manager/motion_event_coalescer.cc
@@ -6,7 +6,9 @@
 
 #include "chromeos/obsolete_logging.h"
 
-namespace chromeos {
+namespace window_manager {
+
+using chromeos::Closure;
 
 MotionEventCoalescer::MotionEventCoalescer(Closure* cb, int timeout_ms)
     : timer_id_(0),
@@ -72,4 +74,4 @@ gboolean MotionEventCoalescer::HandleTimer() {
   return TRUE;
 }
 
-}  // namespace chromeos
+}  // namespace window_manager