[Tracing] Introduce HeapDumpWriter helper class

base/trace_event/trace_event.gypi

 # 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.
 {
   'variables': {
     'trace_event_sources' : [
       'trace_event/exported/trace_event_common.h',
       'trace_event/java_heap_dump_provider_android.cc',
       'trace_event/java_heap_dump_provider_android.h',
       'trace_event/memory_allocator_dump.cc',
       'trace_event/memory_allocator_dump.h',
       'trace_event/memory_allocator_dump_guid.cc',
       'trace_event/memory_allocator_dump_guid.h',
       'trace_event/memory_dump_manager.cc',
       'trace_event/memory_dump_manager.h',
       'trace_event/memory_dump_provider.h',
       'trace_event/memory_dump_request_args.cc',
       'trace_event/memory_dump_request_args.h',
       'trace_event/memory_dump_session_state.cc',
       'trace_event/memory_dump_session_state.h',
       'trace_event/memory_profiler_allocation_context.cc',
       'trace_event/memory_profiler_allocation_context.h',
       'trace_event/memory_profiler_allocation_register.cc',
       'trace_event/memory_profiler_allocation_register_posix.cc',
       'trace_event/memory_profiler_allocation_register_win.cc',
       'trace_event/memory_profiler_allocation_register.h',
+      'trace_event/memory_profiler_heap_dump_writer.cc',
+      'trace_event/memory_profiler_heap_dump_writer.h',
       'trace_event/process_memory_dump.cc',
       'trace_event/process_memory_dump.h',
       'trace_event/process_memory_maps.cc',
       'trace_event/process_memory_maps.h',
       'trace_event/process_memory_maps_dump_provider.h',
       'trace_event/process_memory_totals.cc',
       'trace_event/process_memory_totals.h',
       'trace_event/process_memory_totals_dump_provider.cc',
       'trace_event/process_memory_totals_dump_provider.h',
       'trace_event/trace_buffer.cc',
@@ skipping 48 matching lines @@
             'trace_event/malloc_dump_provider.h',
             'trace_event/process_memory_maps_dump_provider.cc',
           ],
           'trace_event_test_sources' : [
             'trace_event/process_memory_maps_dump_provider_unittest.cc',
           ],
       }],
     ],
   },
 }