Repair/Enable TabCaptureApiTest.FullscreenEvents.

Repair/Enable TabCaptureApiTest.FullscreenEvents.

This test was disabled long ago, before Fullscreen-Within-Tab was
implemented.  When attempting to re-enable, it became clear that
toggling browser fullscreen directly via FullscreenController was not a
workable approach.  This change fixes the issue by instead sending
simulated mouse click events to the renderer, with JS code in the
renderer toggling fullscreen via the HTML5 Fullscreen JS API.

BUG=367349
Committed: https://crrev.com/bd99c31abff6648dadaf101ddded95ff5002959e
Cr-Commit-Position: refs/heads/master@{#305089}

[miu, 2014-11-19 22:33:24]

miu@chromium.org changed reviewers:
+ hubbe@chromium.org

[miu, 2014-11-19 22:33:25]

hubbe: PTAL (this is the 2nd one).

[hubbe, 2014-11-19 23:24:28]

lgtm

[miu, 2014-11-20 21:24:39]

The CQ bit was checked by miu@chromium.org

[commit-bot: I haz the power, 2014-11-20 21:25:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/736793004/40001

[commit-bot: I haz the power, 2014-11-20 22:26:02]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2014-11-20 22:26:38]

Patchset 3 (id:??) landed as
https://crrev.com/bd99c31abff6648dadaf101ddded95ff5002959e
Cr-Commit-Position: refs/heads/master@{#305089}