Fix a use-after-free in ProfileDownloader.

Fix a use-after-free in ProfileDownloader.

Some consumers of the ProfileDownloader class dispose of it in the
OnProfileDownloadSuccess callback. When the profile image is cached
and the image fetch is synchronous, this caused a use-after-free in
ProfileDownloader::OnAccountUpdated().

BUG=518866
Committed: https://crrev.com/643eff5a2fe5ecc38bcb782e36e8cc8ffc5885fd
Cr-Commit-Position: refs/heads/master@{#348724}

[anthonyvd, 2015-09-14 19:45:37]

anthonyvd@chromium.org changed reviewers:
+ rogerta@chromium.org

[anthonyvd, 2015-09-14 19:45:38]

Hi Roger, can you please take a look at this small fix?

Thanks!

[Roger Tawa OOO till Jul 10th, 2015-09-14 20:03:02]

lgtm, see below.

https://codereview.chromium.org/1341113002/diff/1/chrome/browser/profiles/pro...
File chrome/browser/profiles/profile_downloader.cc (right):

https://codereview.chromium.org/1341113002/diff/1/chrome/browser/profiles/pro...
chrome/browser/profiles/profile_downloader.cc:233: FetchImageData();
Maybe add comment here and at line 389 that this should be last call to member,
since object could get deleted.

Nit: add { and } to if and else blocks.

[anthonyvd, 2015-09-14 20:18:39]

The CQ bit was checked by anthonyvd@chromium.org

[anthonyvd, 2015-09-14 20:18:40]

The patchset sent to the CQ was uploaded after l-g-t-m from rogerta@chromium.org
Link to the patchset: https://codereview.chromium.org/1341113002/#ps20001
(title: "Add comments")

[commit-bot: I haz the power, 2015-09-14 20:18:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1341113002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1341113002/20001

[commit-bot: I haz the power, 2015-09-14 21:18:23]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-14 21:19:05]

Patchset 2 (id:??) landed as
https://crrev.com/643eff5a2fe5ecc38bcb782e36e8cc8ffc5885fd
Cr-Commit-Position: refs/heads/master@{#348724}

[commit-bot: I haz the power, 2015-09-23 12:37:28]

Patchset 2 (id:??) landed as
https://crrev.com/643eff5a2fe5ecc38bcb782e36e8cc8ffc5885fd
Cr-Commit-Position: refs/heads/master@{#348724}