Dump /proc/<pid>/maps with every heap profile dump.

third_party/tcmalloc/chromium/src/deep-heap-profile.h

 // Copyright (c) 2012 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.
 
 // ---
 // Author: Sainbayar Sukhbaatar
 //         Dai Mikurube
 //
 // This file contains a class DeepHeapProfile and its public function
 // DeepHeapProfile::FillOrderedProfile() which works as an alternative of
@@ skipping 178 matching lines @@
   // Read a pagemap state from the current pagemap_fd offset.
   // It returns true if succeeded.  Otherwise, it returns false.
   static bool ReadProcPagemap(int pagemap_fd, PageState* state);
 
   // Returns the number of resident (including swapped) bytes of the memory
   // region starting at |first_address| and ending at |last_address| inclusive.
   static size_t GetCommittedSize(int pagemap_fd,
                                  uint64 first_address,
                                  uint64 last_address);
 
-  // Write re-formatted /proc/self/maps into a file which has |filename_prefix|
-  // with using |buffer| of size |buffer_size|.
+  // Write re-formatted /proc/self/maps into a file with using |buffer| of
+  // size |buffer_size|.
+  // If |count| is zero, the filename will be "|filename_prefix|.<pid>.maps".
+  // Otherwise, "|filename_prefix|.<pid>.|count|.maps".
   static void WriteMapsToFile(const char* filename_prefix,
+                              unsigned count,
                               int buffer_size,
                               char buffer[]);
 
   // Compute the global statistics from /proc/self/maps and |pagemap_fd|, and
   // store the statistics in |stats|.
   static void SnapshotGlobalStatsWithoutMalloc(int pagemap_fd,
                                                GlobalStats* stats,
                                                MMapListEntry* mmap_list,
                                                int mmap_list_length);
 
@@ skipping 85 matching lines @@
   int mmap_list_length_;
   int num_mmap_allocations_;
 #endif  // DEEP_HEAP_PROFILE
 
   HeapProfileTable* heap_profile_;
 
   DISALLOW_COPY_AND_ASSIGN(DeepHeapProfile);
 };
 
 #endif  // BASE_DEEP_HEAP_PROFILE_H_