Add CompoundSyncable class for synchronizing containers of Syncables.

blimp/helium/helium_test.h

 // Copyright 2016 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.
 
 #ifndef BLIMP_HELIUM_HELIUM_TEST_H_
 #define BLIMP_HELIUM_HELIUM_TEST_H_
 
 #include "base/at_exit.h"
 #include "base/macros.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blimp {
 namespace helium {
-namespace test {
 
 class HeliumTest : public ::testing::Test {
  public:
   HeliumTest() {}
   ~HeliumTest() override {}
 
  private:
   base::ShadowingAtExitManager at_exit_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(HeliumTest);
 };
 
-}  // namespace test
 }  // namespace helium
 }  // namespace blimp
 
 #endif  // BLIMP_HELIUM_HELIUM_TEST_H_