[DevTools] Set correct overlay size for scaled page.

[DevTools] Set correct overlay size for scaled page.

Overlay was sized to visible size, but it is not scaled together with the page.
Therefore, the correct size is equal to viewport size.

BUG=508136
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201573

[dgozman, 2015-08-31 21:28:27]

dgozman@chromium.org changed reviewers:
+ pfeldman@chromium.org, sergeyv@chromium.org

[dgozman, 2015-08-31 21:28:28]

Take a look please.

[sergeyv, 2015-08-31 23:30:14]

lgtm

[dgozman, 2015-09-01 17:58:22]

ping

[pfeldman, 2015-09-01 19:29:08]

lgtm

[dgozman, 2015-09-01 19:29:50]

The CQ bit was checked by dgozman@chromium.org

[commit-bot: I haz the power, 2015-09-01 19:29:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1327503002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1327503002/1

[commit-bot: I haz the power, 2015-09-01 21:46:47]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201573