Rename MockRendererScheduler to WebMockThreadScheduler.

This CL renames the class MockRendererScheduler which is the mock of
WebThreadScheduler, formerly named RendererScheduler, so it would match
the current name of its parent class and follow the naming convention
for Blink public classes (starting with "Web").

Bug: 826203
Change-Id: Ibda5282749e1379b053ff27bb03b9140fa124f37
Reviewed-on: https://chromium-review.googlesource.com/c/1328547
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Commit-Queue: Yuta Kitamura <yutak@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607160}
3 files changed