Fix mmap region iteration while no regions are recorded.

third_party/tcmalloc/chromium/src/memory_region_map.h

 /* Copyright (c) 2006, Google Inc.
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  * 
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 343 matching lines @@
   inline static void DoInsertRegionLocked(const Region& region);
   // Handle regions saved by InsertRegionLocked into a tmp static array
   // by calling insert_func on them.
   inline static void HandleSavedRegionsLocked(
                        void (*insert_func)(const Region& region));
 
   // Restore buckets saved in a tmp static array by GetBucket to the bucket
   // table where all buckets eventually should be.
   static void RestoreSavedBucketsLocked();
 
+  // Initialize RegionSet regions_.
+  inline static void InitRegionSetLocked();
+
   // Wrapper around DoInsertRegionLocked
   // that handles the case of recursive allocator calls.
   inline static void InsertRegionLocked(const Region& region);
 
   // Record addition of a memory region at address "start" of size "size"
   // (called from our mmap/mremap/sbrk hooks).
   static void RecordRegionAddition(const void* start, size_t size);
   // Record deletion of a memory region at address "start" of size "size"
   // (called from our munmap/mremap/sbrk hooks).
   static void RecordRegionRemoval(const void* start, size_t size);
@@ skipping 29 matching lines @@
   for (int index = 0; index < kHashTableSize; index++) {
     for (HeapProfileBucket* bucket = bucket_table_[index];
          bucket != NULL;
          bucket = bucket->next) {
       callback(bucket, callback_arg);
     }
   }
 }
 
 #endif  // BASE_MEMORY_REGION_MAP_H_