Move gpu hash_tables and atomicops stuff

gpu/command_buffer/client/atomicops.cc

Index: gpu/command_buffer/client/atomicops.cc
diff --git a/gpu/command_buffer/client/atomicops.cc b/gpu/command_buffer/client/atomicops.cc
new file mode 100644
index 0000000000000000000000000000000000000000..142ab9c6f6448d0532333e247e9629f6d366e0e5
--- /dev/null
+++ b/gpu/command_buffer/client/atomicops.cc
@@ -0,0 +1,22 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "../client/atomicops.h"
+
+#if !defined(__native_client__)
+#include "base/atomicops.h"
+#endif
+
+namespace gpu {
+
+void MemoryBarrier() {
+#if defined(__native_client__)
+  __sync_synchronize();
+#else
+  base::subtle::MemoryBarrier();
+#endif
+}
+
+}  // namespace gpu
+