GitLab

Commit d1034e1e ("sensors: Make SensorProviderProxy supplement Document,
not LocalFrame") tied a sensor's lifetime to a document rather than a frame,
but we continued to assume Document::GetFrame() would never return null.

This is not true, as evidenced by the crash reports in bug 889754, caused by
SensorProxy::ShouldSuspendUpdates() trying to invoke methods on a LocalFrame
that can actually be a nullptr.

The original backtrace in the bug report seems to come from sensor creation,
but it is easier to trigger the same crash with a focus change after
destroying a sensor's document's frame.

Bug: 861675, 889754
Change-Id: Idb9ed5c18a655e113e2fb76cde6615aeefcc544a
Reviewed-on: https://chromium-review.googlesource.com/1256826Reviewed-by: Reilly Grant <reillyg@chromium.org>
Commit-Queue: Raphael Kubo da Costa (CET) <raphael.kubo.da.costa@intel.com>
Cr-Commit-Position: refs/heads/master@{#595958}