Move Singleton and related structs to namespace base

content/browser/zygote_host/zygote_host_impl_linux.h

 // 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.
 
 #ifndef CONTENT_BROWSER_ZYGOTE_HOST_ZYGOTE_HOST_IMPL_LINUX_H_
 #define CONTENT_BROWSER_ZYGOTE_HOST_ZYGOTE_HOST_IMPL_LINUX_H_
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/pickle.h"
 #include "base/process/kill.h"
 #include "base/synchronization/lock.h"
 #include "content/public/browser/file_descriptor_info.h"
 #include "content/public/browser/zygote_host_linux.h"
 
+namespace base {
 template<typename Type>
 struct DefaultSingletonTraits;
+}  // namespace base
 
 namespace content {
 
 class CONTENT_EXPORT ZygoteHostImpl : public ZygoteHost {
  public:
   // Returns the singleton instance.
   static ZygoteHostImpl* GetInstance();
 
   void Init(const std::string& sandbox_cmd);
 
@@ skipping 23 matching lines @@
                                                bool known_dead,
                                                int* exit_code);
 
   // ZygoteHost implementation:
   pid_t GetPid() const override;
   int GetSandboxStatus() const override;
   void AdjustRendererOOMScore(base::ProcessHandle process_handle,
                               int score) override;
 
  private:
-  friend struct DefaultSingletonTraits<ZygoteHostImpl>;
+  friend struct base::DefaultSingletonTraits<ZygoteHostImpl>;
 
   ZygoteHostImpl();
   ~ZygoteHostImpl() override;
 
   // Notify the Zygote to exit immediately. This object should not be
   // used afterwards.
   void TearDown();
 
   // Should be called every time a Zygote child is born.
   void ZygoteChildBorn(pid_t process);
@@ skipping 25 matching lines @@
   // A lock protecting list_of_running_zygote_children_ and
   // should_teardown_after_last_child_exits_.
   base::Lock child_tracking_lock_;
   std::set<pid_t> list_of_running_zygote_children_;
   bool should_teardown_after_last_child_exits_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ZYGOTE_HOST_ZYGOTE_HOST_IMPL_LINUX_H_