port d4696c48 (r27150)

original commit message:

  This moves the decision whether to report a message or not to when
  the pending exception is propagated instead of trying to preserve the
  decision in a ThreadLocalTop field.

BUG=

Review URL: https://codereview.chromium.org/1028073002

Cr-Commit-Position: refs/heads/master@{#27360}