Cleanup ChromeHistoryClientFactory

Cleanup ChromeHistoryClientFactory

Change interface of GetForProfile() to return an history::HistoryClient*
instead of a ChromeHistoryClient* since no-one depends on the more typed
return value.

Remove unused GetForProfileWithoutCreating() method which is no longer
used (and the corresponding comment).

BUG=None

Committed: https://crrev.com/68471b7bef6e35835e343a0e9605ed45481aad72
Cr-Commit-Position: refs/heads/master@{#321589}

[sdefresne, 2015-03-19 17:40:32]

sdefresne@chromium.org changed reviewers:
+ jif@chromium.org

[sdefresne, 2015-03-19 17:40:32]

PTAL

[jif, 2015-03-19 18:04:45]

lgtm

[sdefresne, 2015-03-19 18:20:45]

The CQ bit was checked by sdefresne@chromium.org

[commit-bot: I haz the power, 2015-03-19 18:20:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1020913002/1

[sdefresne, 2015-03-19 18:31:06]

The CQ bit was unchecked by sdefresne@chromium.org

[sdefresne, 2015-03-20 16:54:02]

The CQ bit was checked by sdefresne@chromium.org

[sdefresne, 2015-03-20 16:54:03]

The patchset sent to the CQ was uploaded after l-g-t-m from jif@chromium.org
Link to the patchset: https://codereview.chromium.org/1020913002/#ps20001
(title: "Fix android compilation of unit tests")

[commit-bot: I haz the power, 2015-03-20 16:54:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1020913002/20001

[commit-bot: I haz the power, 2015-03-20 17:34:19]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-03-20 17:35:26]

Patchset 2 (id:??) landed as
https://crrev.com/68471b7bef6e35835e343a0e9605ed45481aad72
Cr-Commit-Position: refs/heads/master@{#321589}