Offline Pages: Add NULL-checks for when the model is NULL (incognito mode)

Offline Pages: Add NULL-checks for when the model is NULL (incognito mode)

Recently offline pages was changed to be completely disabled in
incognito profiles, since it is no longer associated with bookmarks, so
some consumers failed to check for null.

BUG=613359
Review-Url: https://codereview.chromium.org/2004473002
Cr-Commit-Position: refs/heads/master@{#395422}
(cherry picked from commit 261c816b0900eec6c3b41277288ccd4020c23f5d)

Committed: https://chromium.googlesource.com/chromium/src/+/2f02d09e1696e7f4df14a0f73712f51397a8f5db

[dewittj, 2016-05-25 16:02:57]

Description was changed from

==========
Offline Pages: Add NULL-checks for when the model is NULL (incognito mode)

Recently offline pages was changed to be completely disabled in
incognito profiles, since it is no longer associated with bookmarks, so
some consumers failed to check for null.

BUG=613359

Review-Url: https://codereview.chromium.org/2004473002
Cr-Commit-Position: refs/heads/master@{#395422}
(cherry picked from commit 261c816b0900eec6c3b41277288ccd4020c23f5d)
==========

to

==========
Offline Pages: Add NULL-checks for when the model is NULL (incognito mode)

Recently offline pages was changed to be completely disabled in
incognito profiles, since it is no longer associated with bookmarks, so
some consumers failed to check for null.

BUG=613359

Review-Url: https://codereview.chromium.org/2004473002
Cr-Commit-Position: refs/heads/master@{#395422}
(cherry picked from commit 261c816b0900eec6c3b41277288ccd4020c23f5d)

Committed:
https://chromium.googlesource.com/chromium/src/+/2f02d09e1696e7f4df14a0f73712...
==========

[dewittj, 2016-05-25 16:02:58]

Committed patchset #1 (id:1) manually as
2f02d09e1696e7f4df14a0f73712f51397a8f5db.