Remove non-standard DeviceOrientation Event initializers.

This patch removes DeviceOrientationEvent.initDeviceOrientationEvent
and DeviceMotionEvent.initDeviceMotionEvent and rewrites the LayoutTests
to use the constructors for these objects instead.

https://www.w3.org/TR/2016/CR-orientation-event-20160818/

BUG=697598

Review-Url: https://codereview.chromium.org/2728963004
Cr-Commit-Position: refs/heads/master@{#457849}
16 files changed