Cleanup remaining class/struct fwd declarations

skia/ext/skia_trace_memory_dump_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 SKIA_EXT_SK_TRACE_MEMORY_DUMP_CHROME_H_
 #define SKIA_EXT_SK_TRACE_MEMORY_DUMP_CHROME_H_
 
 #include <stdint.h>
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/trace_event/memory_dump_request_args.h"
 #include "third_party/skia/include/core/SkTraceMemoryDump.h"
 
 namespace base {
 namespace trace_event {
-class MemoryAllocatorDump;
 class ProcessMemoryDump;
 }
 }
 
 namespace skia {
 
 class SK_API SkiaTraceMemoryDumpImpl : public SkTraceMemoryDump {
  public:
   // This should never outlive the OnMemoryDump call since the
   // ProcessMemoryDump is valid only in that timeframe. Optional
@@ skipping 35 matching lines @@
 
   // Stores the level of detail for the current dump.
   LevelOfDetail request_level_;
 
   DISALLOW_COPY_AND_ASSIGN(SkiaTraceMemoryDumpImpl);
 };
 
 }  // namespace skia
 
 #endif  // SKIA_EXT_SK_TRACE_MEMORY_DUMP_CHROME_H_