Move Singleton and related structs to namespace base

skia/ext/skia_memory_dump_provider.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 SKIA_EXT_SKIA_MEMORY_DUMP_PROVIDER_H_
 #define SKIA_EXT_SKIA_MEMORY_DUMP_PROVIDER_H_
 
 #include "base/memory/singleton.h"
 #include "base/trace_event/memory_dump_provider.h"
 #include "third_party/skia/include/core/SkTypes.h"
 
 namespace skia {
 
 class SK_API SkiaMemoryDumpProvider
     : public base::trace_event::MemoryDumpProvider {
  public:
   static SkiaMemoryDumpProvider* GetInstance();
 
   // base::trace_event::MemoryDumpProvider implementation:
   bool OnMemoryDump(
       const base::trace_event::MemoryDumpArgs& args,
       base::trace_event::ProcessMemoryDump* process_memory_dump) override;
 
  private:
-  friend struct DefaultSingletonTraits<SkiaMemoryDumpProvider>;
+  friend struct base::DefaultSingletonTraits<SkiaMemoryDumpProvider>;
 
   SkiaMemoryDumpProvider();
   ~SkiaMemoryDumpProvider() override;
 
   DISALLOW_COPY_AND_ASSIGN(SkiaMemoryDumpProvider);
 };
 
 }  // namespace skia
 
 #endif  // SKIA_EXT_SKIA_MEMORY_DUMP_PROVIDER_H_