base: Cleanup class/struct forward declarations

base/trace_event/process_memory_dump.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 BASE_TRACE_EVENT_PROCESS_MEMORY_DUMP_H_
 #define BASE_TRACE_EVENT_PROCESS_MEMORY_DUMP_H_
 
 #include <stddef.h>
 
 #include <unordered_map>
@@ skipping 13 matching lines @@
 
 // Define COUNT_RESIDENT_BYTES_SUPPORTED if platform supports counting of the
 // resident memory.
 #if (defined(OS_POSIX) && !defined(OS_NACL)) || defined(OS_WIN)
 #define COUNT_RESIDENT_BYTES_SUPPORTED
 #endif
 
 namespace base {
 namespace trace_event {
 
-class MemoryDumpManager;
 class MemoryDumpSessionState;
 class TracedValue;
 
 // ProcessMemoryDump is as a strongly typed container which holds the dumps
 // produced by the MemoryDumpProvider(s) for a specific process.
 class BASE_EXPORT ProcessMemoryDump {
  public:
   struct MemoryAllocatorDumpEdge {
     MemoryAllocatorDumpGuid source;
     MemoryAllocatorDumpGuid target;
@@ skipping 169 matching lines @@
   // background mode are disabled for testing.
   static bool is_black_hole_non_fatal_for_testing_;
 
   DISALLOW_COPY_AND_ASSIGN(ProcessMemoryDump);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_PROCESS_MEMORY_DUMP_H_