Move Singleton and related structs to namespace base

components/tracing/child_memory_dump_manager_delegate_impl.h

 // Copyright 2015 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 COMPONENTS_TRACING_CHILD_MEMORY_DUMP_MANAGER_DELEGATE_IMPL_H_
 #define COMPONENTS_TRACING_CHILD_MEMORY_DUMP_MANAGER_DELEGATE_IMPL_H_
 
 #include "base/trace_event/memory_dump_manager.h"
 
 #include "base/memory/ref_counted.h"
@@ skipping 35 matching lines @@
         id == base::trace_event::MemoryDumpManager::kInvalidTracingProcessId ||
             id == tracing_process_id_);
     tracing_process_id_ = id;
   }
 
  protected:
   // Make CreateProcessDump() visible to ChildTraceMessageFilter.
   friend class ChildTraceMessageFilter;
 
  private:
-  friend struct DefaultSingletonTraits<ChildMemoryDumpManagerDelegateImpl>;
+  friend struct base::DefaultSingletonTraits<
+      ChildMemoryDumpManagerDelegateImpl>;
 
   ChildMemoryDumpManagerDelegateImpl();
   ~ChildMemoryDumpManagerDelegateImpl() override;
 
   ChildTraceMessageFilter* ctmf_;  // Not owned.
 
   // The SingleThreadTaskRunner where the |ctmf_| lives.
   // It is NULL iff |cmtf_| is NULL.
   scoped_refptr<base::SingleThreadTaskRunner> ctmf_task_runner_;
 
   // The unique id of the child process, created for tracing and is expected to
   // be valid only when tracing is enabled.
   uint64 tracing_process_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ChildMemoryDumpManagerDelegateImpl);
 };
 
 }  // namespace tracing
 
 #endif  // COMPONENTS_TRACING_CHILD_MEMORY_DUMP_MANAGER_DELEGATE_IMPL_H_