Remove null entries from UMA stats SharedPrefs

Remove null entries from UMA stats SharedPrefs

DownloadUmaStatsEntry.parseFromString() could potentially return null.
And that null is added to the list in DownloadManagerService.
This could potentially cause a crash.
This CL avoids adding null to the list, and also fixes an error in parsing the string.

BUG=704220
Review-Url: https://codereview.chromium.org/2767143006
Cr-Commit-Position: refs/heads/master@{#460026}
Committed: https://chromium.googlesource.com/chromium/src/+/05a0df9c9908ceabcf5febca6daecb87dd1ae5f0

[qinmin, 2017-03-24 22:01:17]

qinmin@chromium.org changed reviewers:
+ dtrainor@chromium.org

[qinmin, 2017-03-24 22:01:17]

qinmin@chromium.org changed reviewers:
+ dtrainor@chromium.org

[qinmin, 2017-03-24 22:01:17]

PTAL

[qinmin, 2017-03-24 22:01:18]

PTAL

[David Trainor- moved to gerrit, 2017-03-28 03:06:52]

lgtm

[qinmin, 2017-03-28 05:32:31]

The CQ bit was checked by qinmin@chromium.org

[commit-bot: I haz the power, 2017-03-28 05:32:53]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-28 06:10:32]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1490679151082030, "parent_rev":
"c802941a91a0b6427e8cda5775f7bf728939e7de", "commit_rev":
"05a0df9c9908ceabcf5febca6daecb87dd1ae5f0"}

[commit-bot: I haz the power, 2017-03-28 06:11:56]

Description was changed from

==========
Remove null entries from UMA stats SharedPrefs

DownloadUmaStatsEntry.parseFromString() could potentially return null.
And that null is added to the list in DownloadManagerService.
This could potentially cause a crash.
This CL avoids adding null to the list, and also fixes an error in parsing the
string.

BUG=704220
==========

to

==========
Remove null entries from UMA stats SharedPrefs

DownloadUmaStatsEntry.parseFromString() could potentially return null.
And that null is added to the list in DownloadManagerService.
This could potentially cause a crash.
This CL avoids adding null to the list, and also fixes an error in parsing the
string.

BUG=704220

Review-Url: https://codereview.chromium.org/2767143006
Cr-Commit-Position: refs/heads/master@{#460026}
Committed:
https://chromium.googlesource.com/chromium/src/+/05a0df9c9908ceabcf5febca6dae...
==========

[commit-bot: I haz the power, 2017-03-28 06:11:57]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/05a0df9c9908ceabcf5febca6dae...