[SendTabToSelf] Potentially fixed sigsev in ShouldOfferFeature.

The function assumed that all calls would return non-null pointers.
Fixed that to explictly check for nullptr.

Bug: 950640
Change-Id: I7b1ff107b3dd6b94b439f486779cfefe2ae1688e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1577977
Reviewed-by: sebsg <sebsg@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Tanya Gupta <tgupta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653360}
1 file changed