Detailed report: https://clusterfuzz.com/testcase?key=5421460765802496

Fuzzer: inferno_layout_test_unmodified
Job Type: linux_ubsan_vptr_chrome
Platform Id: linux

Crash Type: Null-dereference READ
Crash Address: 0x000000000000
Crash State:
  blink::InlineBox::LogicalLeft
  blink::RootInlineBox::ClosestLeafChildForLogicalLeftPosition
  blink::RootInlineBox::ClosestLeafChildForPoint
  
Sanitizer: undefined (UBSAN)

Regressed: https://clusterfuzz.com/revisions?job=linux_ubsan_vptr_chrome&range=508795:508862

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5421460765802496

Issue filed automatically.

See https://github.com/google/clusterfuzz-tools for instructions to reproduce this bug locally.