aura/cros: Rename MessagePump{X => AuraX11} and move the atom cache into it.

ui/aura/env.h

Index: ui/aura/env.h
diff --git a/ui/aura/env.h b/ui/aura/env.h
index 6ffb74fa6d2e9a671bf48a14f84d9d6f49e8f054..033456561f3dc2451bd78d50b9c5fb07dad52487 100644
--- a/ui/aura/env.h
+++ b/ui/aura/env.h
@@ -12,10 +12,6 @@
 #include "ui/aura/aura_export.h"
 #include "ui/aura/client/stacking_client.h"
 
-#if defined(USE_X11)
-#include "ui/aura/x11_atom_cache.h"
-#endif
-
 namespace aura {
 
 class EnvObserver;
@@ -59,12 +55,6 @@ class AURA_EXPORT Env {
   MonitorManager* monitor_manager() { return monitor_manager_.get(); }
   void SetMonitorManager(MonitorManager* monitor_manager);
 
-#if defined(USE_X11)
-  // Gets the X11 atom cache. This must not persist the cache across
-  // Env::DeleteInstance() calls.
-  X11AtomCache* atom_cache() { return &atom_cache_; }
-#endif
-
   // Returns the native event dispatcher. The result should only be passed to
   // MessageLoopForUI::RunWithDispatcher() or
   // MessageLoopForUI::RunAllPendingWithDispatcher(), or used to dispatch
@@ -93,7 +83,6 @@ class AURA_EXPORT Env {
 
 #if defined(USE_X11)
   scoped_ptr<internal::MonitorChangeObserverX11> monitor_change_observer_;
-  X11AtomCache atom_cache_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(Env);