When sampling has disabled crash reporting for WebView, no signal
handler is initialized, causing later calls to DumpWithoutCrash()
to crash.
Bug: 949295
Change-Id: Ib93986f81bc83404ac9f4d8f40fb34e54f1b3bec
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/1558817
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Joshua Peraza <jperaza@chromium.org>