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

Author: mstensho
Project: chromium
Changelist: https://chromium.googlesource.com/chromium/src/+/0740b0dfd20e2f99cddc773e0fe1460ef05da508
Time: Sun Dec 04 10:58:08 2016
Lines 406-420 of file LayoutBlockFlow.cpp which potentially caused crash are changed in this cl (frame #4, "blink::LayoutBlockFlow::layoutBlock").
Minimum distance from crash line to modified line: 0. (file: LayoutBlockFlow.cpp, crashed on: 409, modified: 409). 

Author: mstensho
Project: chromium
Changelist: https://chromium.googlesource.com/chromium/src/+/9d96126f67850daf3c07586dc09fa334d592529c
Time: Mon Dec 05 21:31:06 2016
Lines 405-422, 427-437 of file LayoutBlockFlow.cpp which potentially caused crash are changed in this cl (frame #4, "blink::LayoutBlockFlow::layoutBlock").
Minimum distance from crash line to modified line: 0. (file: LayoutBlockFlow.cpp, crashed on: 409, modified: 409). 

Author: mstensho
Project: chromium
Changelist: https://chromium.googlesource.com/chromium/src/+/053608703a4f735d5bf48fdef38e76f4d4678c9c
Time: Wed Nov 30 23:26:43 2016
Lines 422-425 of file LayoutBlockFlow.cpp which potentially caused crash are changed in this cl (frame #4, "blink::LayoutBlockFlow::layoutBlock").
Minimum distance from crash line to modified line: 0. (file: LayoutBlockFlow.cpp, crashed on: 422, modified: 422).

@mstensho -- 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 440242:440280.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=5252612439146496

Fuzzer: ifratric-browserfuzzer-v3
Job Type: linux_ubsan_chrome
Platform Id: linux

Crash Type: Float-cast-overflow
Crash Address: 
Crash State:
  blink::LayoutBlock::columnGap
  blink::LayoutMultiColumnFlowThread::calculateColumnCountAndWidth
  blink::LayoutMultiColumnFlowThread::needsNewWidth
  
Regressed: https://cluster-fuzz.appspot.com/revisions?job=linux_ubsan_chrome&range=435261:438085
Fixed: https://cluster-fuzz.appspot.com/revisions?job=linux_ubsan_chrome&range=440242:440280

Minimized Testcase (0.13 Kb): https://cluster-fuzz.appspot.com/download/AMIfv96JoPqTbW7P3f0n6pco43ylnmPysQ2rrt-Gdeq76H2MtKzgt8Oj0Y_iEc9sK1bq8AWZhuoh1Rl5PHHCgcXjq7QiMpUobF9BRX-_mwucVi1i11g1oFgnYl7MrpOBrJCRSW6y6Rvyb2sbI5JGHWQlxHOcdHZ0wg?testcase_id=5252612439146496

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.

ClusterFuzz testcase 5252612439146496 is verified as fixed, so closing issue.

If this is incorrect, please add ClusterFuzz-Wrong label and re-open the issue.