Prepend "Web" to RenderWidgetSchedulingState.

This class is Blink's public interface, so its name should start with
"Web".

This is a follow-up of crrev.com/c/986112.

Bug: 826203
Change-Id: I88933aa86fbe64c695cc10a76ce36edc1b981f7a
Reviewed-on: https://chromium-review.googlesource.com/989386
Reviewed-by: Alexander Timin <altimin@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Yuta Kitamura <yutak@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548734}
16 files changed