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

Author: alancutter
Project: chromium
Changelist: https://chromium.googlesource.com/chromium/src/+/f9262a06c8d1e0478cbf2cc84a1b29f86d9d89e4
Time: Mon Dec 05 05:51:15 2016
File StyleResolver.cpp is changed in this cl (and is part of stack frame #5, "void blink::StyleResolver::applyProperties<"; frame #6, "void blink::StyleResolver::applyMatchedProperties<")
Minimum distance from crash line to modified line: 7. (file: StyleResolver.cpp, crashed on: 1619, modified: 1626). 

Author: ericwilligers
Project: chromium
Changelist: https://chromium.googlesource.com/chromium/src/+/f8be9028bcafa8722452bf454d11b2dc6304f0f8
Time: Fri Dec 09 04:15:47 2016
File StyleBuilderConverter.cpp is changed in this cl (and is part of stack frame #2, "blink::StyleBuilderConverter::convertLength"; frame #3, "blink::StyleBuilderConverter::convertLengthSizing")
Minimum distance from crash line to modified line: 57. (file: StyleBuilderConverter.cpp, crashed on: 803, modified: 860).

@alancutter -- 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=5984063757484032

Fuzzer: inferno_twister
Job Type: linux_ubsan_chrome
Platform Id: linux

Crash Type: Float-cast-overflow
Crash Address: 
Crash State:
  Length
  blink::CSSPrimitiveValue::convertToLength
  blink::StyleBuilderConverter::convertLength
  
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 (0.76 Kb): https://cluster-fuzz.appspot.com/download/AMIfv97OgLKIUSXc7ewEszCqci96oeL_SMLcAzcMNu3RuIyF2rc1aFSGwXid8B1zr9l6DG2rQrwPf3fDniHCGt0K5Z7jWbjEZSYjlP5NHvTD5BjKBj37YRRrgq9JTvnUFpmI3dhJNkwCLRyQPrftE5JrpTYcmGBUUA?testcase_id=5984063757484032

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.