Fixed segmentation fault. Because currently return null when call views::LinuxUI::instance().

Fixed Segmentation fault. Because currently return null when call views::LinuxUI::instance().

This CL is to fix Segmentation fault on content_shell.
Because currently return null when call views::LinuxUI::instance().
So replace views::LinuxUI::instance()->GetDeviceScaleFactor() with GetDeviceScaleFactor().
Base OS:Ubuntu 14.04(64bit)

BUG=476360

[hyunjunekim2, 2015-04-12 07:20:08]

hyunjune.kim@samsung.com changed reviewers:
+ erg@google.com, reveman@chromium.org, sadrul@chromium.org, sky@chromium.org,
tapted@chromium.org

[hyunjunekim2, 2015-04-12 07:21:13]

Hi, I'm hyunjunekim (hyunjune.kim@samsung.com,
hykim0777@gamil.com). this CL is to fix bug(476360). Could you check this one?

[tapted, 2015-04-12 23:34:34]

tapted@chromium.org changed reviewers:
+ oshima@chromium.org
- reveman@chromium.org, sadrul@chromium.org, sky@chromium.org,
tapted@chromium.org

[tapted, 2015-04-12 23:34:35]

+oshima/erg are probably the best reviewers for this, since they reviewed
r324782. Moving everyone else to cc.

Also +stapelberg since it looks like this is kinda a regression from r324782

[hyunjunekim2, 2015-04-13 10:17:08]

On 2015/04/12 23:34:35, tapted wrote:
> +oshima/erg are probably the best reviewers for this, since they reviewed
> r324782. Moving everyone else to cc.
> 
> Also +stapelberg since it looks like this is kinda a regression from r324782

This issue was fixed by this patch(https://codereview.chromium.org/1079883002).

[stapelberg, 2015-04-13 10:32:56]

stapelberg@google.com changed reviewers:
+ stapelberg@google.com

[stapelberg, 2015-04-13 10:32:56]

The fix LGTM, but I’m not sure how best to proceed, given that the code in
question was rolled back. Unless anyone objects, I’ll send a CL which re-adds it
with this fix.

[stapelberg, 2015-04-13 10:33:16]

On 2015/04/13 10:32:56, stapelberg wrote:
> The fix LGTM, but I’m not sure how best to proceed, given that the code in
> question was rolled back. Unless anyone objects, I’ll send a CL which re-adds
it
> with this fix.

Ah, I see this issue is already closed. Nevermind :).

[hyunjunekim2, 2015-04-13 12:01:19]

On 2015/04/13 10:33:16, stapelberg wrote:
> On 2015/04/13 10:32:56, stapelberg wrote:
> > The fix LGTM, but I’m not sure how best to proceed, given that the code in
> > question was rolled back. Unless anyone objects, I’ll send a CL which
re-adds
> it
> > with this fix.
> 
> Ah, I see this issue is already closed. Nevermind :).

stapelberg, Thank you for your review. ;)