Add CHECK on session start for profile construction

Add CHECK on session start for profile construction

Fail fast from the profile construction when it's triggered without
starting a session first.

Crashing the browser is arguably a worth thing to do, as it prevents
running the browser in unexpected environment (which may lead to, for
instance, bypassing the managed policies).

Also this CHECK should provide the stack traces which are more likely to
point to the culprit code (as opposed to crashing at some later point
asynchronously - like e.g. on the CHECK added at
https://crrev.com/2801993002).

BUG=719939
TEST=existing browser tests;
    manual tests: normal login; Guest login; restart-after-crash.

Review-Url: https://codereview.chromium.org/2868043002
Cr-Original-Commit-Position: refs/heads/master@{#470524}
Review-Url: https://codereview.chromium.org/2878233003 .
Cr-Commit-Position: refs/branch-heads/3071@{#544}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed: https://chromium.googlesource.com/chromium/src/+/4582fd82174a35a2cf098d6d9408a216d1f8b34b

[emaxx, 2017-05-13 17:54:40]

Description was changed from

==========
Add CHECK on session start for profile construction

Fail fast from the profile construction when it's triggered without
starting a session first.

Crashing the browser is arguably a worth thing to do, as it prevents
running the browser in unexpected environment (which may lead to, for
instance, bypassing the managed policies).

Also this CHECK should provide the stack traces which are more likely to
point to the culprit code (as opposed to crashing at some later point
asynchronously - like e.g. on the CHECK added at
https://crrev.com/2801993002).

BUG=719939
TEST=existing browser tests;
    manual tests: normal login; Guest login; restart-after-crash.

Review-Url: https://codereview.chromium.org/2868043002
Cr-Commit-Position: refs/heads/master@{#470524}
(cherry picked from commit f588c3bceb117e579068d1b4b3bb4153642d941d)
==========

to

==========
Add CHECK on session start for profile construction

Fail fast from the profile construction when it's triggered without
starting a session first.

Crashing the browser is arguably a worth thing to do, as it prevents
running the browser in unexpected environment (which may lead to, for
instance, bypassing the managed policies).

Also this CHECK should provide the stack traces which are more likely to
point to the culprit code (as opposed to crashing at some later point
asynchronously - like e.g. on the CHECK added at
https://crrev.com/2801993002).

BUG=719939
TEST=existing browser tests;
    manual tests: normal login; Guest login; restart-after-crash.

Review-Url: https://codereview.chromium.org/2868043002
Cr-Original-Commit-Position: refs/heads/master@{#470524}
Review-Url: https://codereview.chromium.org/2878233003 .
Cr-Commit-Position: refs/branch-heads/3071@{#544}
Cr-Branched-From:
a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed:
https://chromium.googlesource.com/chromium/src/+/4582fd82174a35a2cf098d6d9408...
==========

[emaxx, 2017-05-13 17:54:42]

Committed patchset #1 (id:1) manually as
4582fd82174a35a2cf098d6d9408a216d1f8b34b.