Fix for handling alt+Left Arrow key for moving to previous visited URL.

Fix for handling alt+Left Arrow key for moving to previous visited URL.

currently behavior of alt+Left arrow key and Left Arrow key are same.
Check added so that when user select alt+Left arrow key then it will
be handled by default behavior.

BUG=468605
Committed: https://crrev.com/20ff333d6d95a00e8b203a501781aa8481127493
Cr-Commit-Position: refs/heads/master@{#321516}

[Deepak, 2015-03-19 04:55:29]

deepak.m1@samsung.com changed reviewers:
+ bauerb@chromium.org, dbeam@chromium.org

[Deepak, 2015-03-19 04:55:29]

@dbeam
PTAL at small change for handling alt+Left arrow key for moving to the previous
visited URL like choosing 'Back' from context menu.
Thanks

[Dan Beam, 2015-03-19 19:51:56]

dbeam@chromium.org changed reviewers:
+ hcarmona@chromium.org

[Dan Beam, 2015-03-19 19:51:56]

+hcarmona

[hcarmona, 2015-03-19 20:24:12]

lgtm

[Dan Beam, 2015-03-19 20:43:54]

lgtm

[Deepak, 2015-03-20 02:47:04]

On 2015/03/19 20:43:54, Dan Beam wrote:
> lgtm

Thankyou Hactor and Dan for review.

[Deepak, 2015-03-20 02:47:09]

The CQ bit was checked by deepak.m1@samsung.com

[commit-bot: I haz the power, 2015-03-20 02:47:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1019193002/1

[commit-bot: I haz the power, 2015-03-20 04:30:23]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-20 04:31:29]

Patchset 1 (id:??) landed as
https://crrev.com/20ff333d6d95a00e8b203a501781aa8481127493
Cr-Commit-Position: refs/heads/master@{#321516}