commit 1ae9287a1aec534fa0a805a717f1c4e058ae8433
author Jason Evans <je@fb.com> Wed Mar 30 18:36:04 2016 -0700
committer Christopher Ferris <cferris@google.com> Wed May 04 12:33:28 2016 -0700
tree d63fb44281c89b0d5f2019d2edf4930cfb8c596e
parent 1e14731d7182460d082d128660d419b26b9c6c39

Fix potential chunk leaks.

Move chunk_dalloc_arena()'s implementation into chunk_dalloc_wrapper(),
so that if the dalloc hook fails, proper decommit/purge/retain cascading
occurs.  This fixes three potential chunk leaks on OOM paths, one during
dss-based chunk allocation, one during chunk header commit (currently
relevant only on Windows), and one during rtree write (e.g. if rtree
node allocation fails).

Merge chunk_purge_arena() into chunk_purge_default() (refactor, no
change to functionality).

Bug: 28590121

(cherry picked from commit 8d8960f635c63b918ac54e0d1005854ed7a2692b)

Change-Id: I70758757b3342e0623918bb56c602873a367a192