The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b88eb54523ddaba65174cd35e4ad6f1cc649d70d

commit b88eb54523ddaba65174cd35e4ad6f1cc649d70d
Author: Marijn Kruisselbrink <mek@chromium.org>
Date: Wed Apr 04 02:05:02 2018

Get rid of Platform::FileTaskRunner.

This is no longer used in blink (and shouldn't be used anymore), so can
safely be removed. Also removes RenderThreadImpl::GetFileThreadTaskRunner,
and moves its usage to create task runners closer to where they are used.

Bug:  828364 
Change-Id: I1c72edfd8da56b21d93ce76d24277ad5ef582383
Reviewed-on: https://chromium-review.googlesource.com/992817
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547950}
[modify] https://crrev.com/b88eb54523ddaba65174cd35e4ad6f1cc649d70d/content/renderer/pepper/host_globals.cc
[modify] https://crrev.com/b88eb54523ddaba65174cd35e4ad6f1cc649d70d/content/renderer/pepper/host_globals.h
[modify] https://crrev.com/b88eb54523ddaba65174cd35e4ad6f1cc649d70d/content/renderer/render_frame_impl.cc
[modify] https://crrev.com/b88eb54523ddaba65174cd35e4ad6f1cc649d70d/content/renderer/render_thread_impl.cc
[modify] https://crrev.com/b88eb54523ddaba65174cd35e4ad6f1cc649d70d/content/renderer/render_thread_impl.h
[modify] https://crrev.com/b88eb54523ddaba65174cd35e4ad6f1cc649d70d/third_party/WebKit/Source/platform/exported/Platform.cpp
[modify] https://crrev.com/b88eb54523ddaba65174cd35e4ad6f1cc649d70d/third_party/WebKit/public/platform/Platform.h