[WebView] Enable scrolling in fullscreen.

[WebView] Enable scrolling in fullscreen.

The next step is to fix crbug/423381 to improve
transitions from/to fullscreen after scrolling.

BUG=398485
Committed: https://crrev.com/4f91ee56e740bc766dfd8964a3adbb776465cf87
Cr-Commit-Position: refs/heads/master@{#300520}

[Ignacio Solla, 2014-10-21 12:30:37]

igsolla@chromium.org changed reviewers:
+ mkosiba@chromium.org

[mkosiba (inactive), 2014-10-21 15:52:19]

lgtm

[Ignacio Solla, 2014-10-21 17:07:09]

The CQ bit was checked by igsolla@chromium.org

[commit-bot: I haz the power, 2014-10-21 17:09:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/653633005/1

[commit-bot: I haz the power, 2014-10-21 17:59:14]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-21 18:00:01]

Patchset 1 (id:??) landed as
https://crrev.com/4f91ee56e740bc766dfd8964a3adbb776465cf87
Cr-Commit-Position: refs/heads/master@{#300520}