Assigning to the concern owner from Predator results --
The result is a list of CLs that change the crashed files. 

Author: yosin
Project: chromium
Changelist: https://chromium.googlesource.com/chromium/src/+/2211504ac2b999a125b2215ce7f6be9e50878fea
Time: Thu Mar 02 12:28:15 2017
Lines 2903 of file VisibleUnits.cpp which potentially caused crash are changed in this cl (frame #4, "mostBackwardCaretPosition >"). 

File PositionIterator.cpp is changed in this cl (and is part of stack frame #3, "blink::PositionIteratorAlgorithm >::PositionIteratorAlgorithm")
Minimum distance from crash line to modified line: 0. (file: VisibleUnits.cpp, crashed on: 2903, modified: 2903).

@yosin -- Could you please look into the issue, kindly re-assign if this is not related to your changes.
Thank You.

ClusterFuzz has detected this issue as fixed in range 456626:457730.

Detailed report: https://clusterfuzz.com/testcase?key=6206442010050560

Fuzzer: ifratric-browserfuzzer-v3
Job Type: mac_asan_chrome
Platform Id: mac

Crash Type: UNKNOWN READ
Crash Address: 0x000000000010
Crash State:
  blink::PositionIteratorAlgorithm<blink::EditingAlgorithm<blink::NodeTraversal> >
  blink::mostBackwardCaretPosition
  blink::canonicalPositionOf
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=mac_asan_chrome&range=454233:454289
Fixed: https://clusterfuzz.com/revisions?job=mac_asan_chrome&range=456626:457730

Reproducer Testcase: https://clusterfuzz.com/download/AMIfv96wFEMvrl5ixQ3sMD0bq9L1ldzxJVPQ9xoIBGbsq2bCCmEH4Ni-GBhIO7gBnIvzVziqlDGFo5jFKxDWDxDmz2d6Lv601N6nlNnlrnDZou-cJzTIxWwoFckKHMKDBBBBOW44BvtCpT-TL6nW_Wt5FJNxOGCfaKTpyzEy2P_yLX1cSpROtBl2z_-5FrxVIlvEivJngfieLRfX48RAJ6go4CtTSHWijD2WtcHaIeZnSTy6xnLkpA9opZmY90rRycsOXIFnu5ArTNFKTRZKfl8s8zQVWStLLDE9tS5a5yqXlAK-NjSbTM6qhxzmrUk3es6Sckgr5-UFIFNGrhOPcq1ZsQW2Xsp5fYbH0Xl1AUGYRaHAc3Opiso?testcase_id=6206442010050560


See https://dev.chromium.org/Home/chromium-security/bugs/reproducing-clusterfuzz-bugs for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.