Add null check in LocationIconDecoration::OnMousePressed.

Add null check in LocationIconDecoration::OnMousePressed.

BUG=445788
TEST=window.open(""), then click page info icon.

Committed: https://crrev.com/f328a3db0a43b6f58ad85e5aae8a3715b64eeff1
Cr-Commit-Position: refs/heads/master@{#309975}

[Charlie Reis, 2015-01-05 21:29:35]

creis@chromium.org changed reviewers:
+ avi@chromium.org

[Charlie Reis, 2015-01-05 21:31:21]

Avi, can you take a look?  Looks like the old check was removed here:
https://codereview.chromium.org/287543002

(Then again, the old check was wrong because it had a NOTREACHED.)

Do you know if there's a way to reach this function in a test?  We could ensure
that it works after window.open("").

[Avi (use Gerrit), 2015-01-05 21:39:24]

LGTM

[Charlie Reis, 2015-01-05 22:03:57]

On 2015/01/05 21:39:24, Avi wrote:
> LGTM

Thanks.  I didn't see an easy way to test, so I'll proceed with this.

[Charlie Reis, 2015-01-05 22:04:00]

The CQ bit was checked by creis@chromium.org

[commit-bot: I haz the power, 2015-01-05 22:04:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/834173002/1

[commit-bot: I haz the power, 2015-01-05 22:52:53]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-05 22:53:49]

Patchset 1 (id:??) landed as
https://crrev.com/f328a3db0a43b6f58ad85e5aae8a3715b64eeff1
Cr-Commit-Position: refs/heads/master@{#309975}