Enable the bubble UI by default on Linux(not including Cros) and Win.
On Chrome OS, the original infobar is still shown.
Use the histogram "SessionCrashed.Bubble" bucket value to verify that the session crash bubble is shown under non-official build.
Under Google Chrome build, this is not tested because
1) a task is posted to the file thread before the bubble is shown
2) it is difficult to make sure that the histogram check runs after all threads have finished their tasks.
BUG=364670
Review URL: https://codereview.chromium.org/
691543002
Cr-Commit-Position: refs/heads/master@{#301958}