Do not clobber the packaged app's default opacity

ChromeOS windows are transparent by default. This allows the window header to be transparent when there is only one window on screen. This CL fixes a case where we were clobbering the window's default opacity.

BUG=312441
TEST=See bug

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=232898

[pkotwicz, 2013-11-02 00:52:14]

benwells@ can you please take a look?

[benwells, 2013-11-04 00:51:03]

lgtm

[commit-bot: I haz the power, 2013-11-04 06:33:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pkotwicz@chromium.org/56623003/1

[commit-bot: I haz the power, 2013-11-04 08:55:29]

Retried try job too often on win7_aura for step(s) browser_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win7_aura&...

[commit-bot: I haz the power, 2013-11-04 16:13:07]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pkotwicz@chromium.org/56623003/1

[commit-bot: I haz the power, 2013-11-04 17:49:07]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pkotwicz@chromium.org/56623003/1

[commit-bot: I haz the power, 2013-11-04 23:22:13]

Retried try job too often on win7_aura for step(s) browser_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win7_aura&...

[commit-bot: I haz the power, 2013-11-05 00:25:54]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pkotwicz@chromium.org/56623003/1

[commit-bot: I haz the power, 2013-11-05 03:20:40]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pkotwicz@chromium.org/56623003/1

[commit-bot: I haz the power, 2013-11-05 04:14:08]

Change committed as 232898