tcmalloc: Fix mmap region iteration while no regions are recorded.

Original CL:

- https://codereview.chromium.org/14769008

  Fix mmap region iteration while no regions are recorded.

  If no mmap regions are recorded, iteration failed since the RegionSet
  (std::set) object is not initialized.

  BUG=162208
  R=willchan@chromium.org

  Committed:
  https://src.chromium.org/viewvc/chrome?view=rev&revision=198878

BUG=724399,b:70905156

Change-Id: I9659e486e5be89e6c36bcdf83d794dee3295e91b
Reviewed-on: https://chromium-review.googlesource.com/c/1130807
Reviewed-by: Will Harris <wfh@chromium.org>
Commit-Queue: Gabriel Marin <gmx@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#596896}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: a427548aa172d8893b1e49980d539ddd606bf43f
2 files changed
tree: e5a3663774bfa8ff3ddfcd3723df3ea0a00e90f7
  1. src/