GitLab

StartupTabProvider may be called when Chrome starts in an incognito profile,
which leads to a crash at start-up. This CL addresses this and adds a unit
test to make sure it does not regress in the future.

Bug: 769241
Change-Id: Idea489bc05e31d7ac693cb935b1481979099bd09
Reviewed-on: https://chromium-review.googlesource.com/689535Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Mihai Sardarescu <msarda@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505395}