Merge the fullscreen event queues

Merge the fullscreen event queues

The two queues are both processed by a single timer, so they might just
as well be a single queue, which also avoids looping over each queue
separately.

Instead of queuing Nodes, Events are created and queued. This means that
the event type is made explicit, which will make it simpler to support
both prefixed and unprefixed events using the same code.

BUG=383813
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177509

[philipj_slow, 2014-07-02 23:20:55]

PTAL. This depends on https://codereview.chromium.org/365993002/ so no try bots
until that's landed, but LayoutTests/fullscreen/ tests pass locally.

[philipj_slow, 2014-07-03 19:43:36]

rebase

[philipj_slow, 2014-07-03 20:01:16]

introduce enqueueChangeEvent/enqueueErrorEvent

[falken, 2014-07-04 01:42:16]

On 2014/07/03 20:01:16, philipj wrote:
> introduce enqueueChangeEvent/enqueueErrorEvent

nice change! lgtm

[philipj_slow, 2014-07-04 05:28:43]

The CQ bit was checked by philipj@opera.com

[commit-bot: I haz the power, 2014-07-04 05:28:58]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/philipj@opera.com/365903006/40001

[commit-bot: I haz the power, 2014-07-04 05:38:47]

Change committed as 177509