Remove early returns from RenderLayerCompositor::setNeedsCompositingUpdate.

This function just sets dirty bits, enables compositing mode
and schedules a visual update. The early returns aren't
needed for correctness and there's nothing performance
sensitive here.

Review URL: https://codereview.chromium.org/247923003

git-svn-id: svn://svn.chromium.org/blink/trunk@172328 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Allow touch events to be uncancelable

The touchevents specification says (http://www.w3.org/TR/touch-events/#list-of-touchevent-types) that touchcancel events should not be cancelable.

We'd also like to allow other touch events (touchmove and touchend) to sometimes be uncancelable (sent async) as well, so rather than special-case touchcancel here we plumb a bit from the browser.  This leaves the decision over which events are cancelable purely in the hands of the browser (except for edge cases around synthetic events), which makes sense because only the browser can know whether it plans to wait for an ACK for the event before proceeding with gesture recognition.

Note that I can't properly test this in a layout test without changing EventSender in the chromium repo, but I can't change EventSender until WebTouchEvent has changed.  So there's no avoiding a 3-sided patch here.  Once the first 2 CLs have landed I'll land a new LayoutTest before marking bug 365681 as Fixed.

BUG=365681, 361306

Review URL: https://codereview.chromium.org/247483002

git-svn-id: svn://svn.chromium.org/blink/trunk@172329 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove the early returns in FrameView::updateCompositingLayersAfterStyleChange.

This function used to do a lot, so the early return was needed
as a performance optimization. Now this function just sets
some dirty bits and sometimes does a bit more work, so we
don't need the early returns.

Review URL: https://codereview.chromium.org/247223006

git-svn-id: svn://svn.chromium.org/blink/trunk@172330 bbb929c8-8fbe-4397-9dbb-9b2b20218538