Fix CrOS SampleApp

Fix CrOS SampleApp

Add compile-time check for GPU build when using GPU flag

TBR=robertphillips@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://skia.googlesource.com/skia/+/41518ebc82152720b15768ee509d299bcd203b47

[jvanverth1, 2015-10-02 17:16:49]

The CQ bit was checked by jvanverth@google.com

[commit-bot: I haz the power, 2015-10-02 17:16:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1376423004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1376423004/1

[jvanverth1, 2015-10-02 17:39:03]

The CQ bit was unchecked by jvanverth@google.com

[jvanverth1, 2015-10-02 17:39:08]

The CQ bit was checked by jvanverth@google.com

[commit-bot: I haz the power, 2015-10-02 17:39:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1376423004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1376423004/1

[jvanverth1, 2015-10-02 17:41:59]

The CQ bit was unchecked by jvanverth@google.com

[jvanverth1, 2015-10-02 17:42:16]

The CQ bit was checked by jvanverth@google.com

[commit-bot: I haz the power, 2015-10-02 17:42:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1376423004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1376423004/1

[commit-bot: I haz the power, 2015-10-02 17:42:39]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/41518ebc82152720b15768ee509d299bcd203b47