Added checking for single window metro mode in restartplatformapp.

Added checking for single window metro mode in restartplatformapp.
The bug seems to have caused as side effect of https://chromiumcodereview.appspot.com/18861009/.
(For correct fix I think we need to think through the entire launch/restart path for metro along with visual UI changes for metro.)

BUG=267498
R=koz,benwells
TEST=Please follow steps as mentioned in the bug report.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=216110

[koz (OOO until 15th September), 2013-08-07 01:50:02]

lgtm, thanks!

https://codereview.chromium.org/22379003/diff/1/chrome/browser/extensions/pla...
File chrome/browser/extensions/platform_app_launcher.cc (right):

https://codereview.chromium.org/22379003/diff/1/chrome/browser/extensions/pla...
chrome/browser/extensions/platform_app_launcher.cc:336: if
(win8::IsSingleWindowMetroMode()) {
nit: no curlies

[benwells, 2013-08-07 01:50:57]

lgtm

[commit-bot: I haz the power, 2013-08-07 03:10:35]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/[email protected]/22379003/7001

[commit-bot: I haz the power, 2013-08-07 06:10:12]

Change committed as 216110