The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ec19b70f6e22218eb829fd458dfc0435937b5377

commit ec19b70f6e22218eb829fd458dfc0435937b5377
Author: Xida Chen <xidachen@chromium.org>
Date: Wed Aug 15 01:57:14 2018

Set touch action to auto when a GSU is resend to embedder

On a touchscreen desktop, when we open a pdf and scroll it, the GSB and
GSE is send to the pdf (guest) view, while the GSU is send to its
embedder. In this case, the embedder may not have touch action set which
could lead to a crash.

This CL fixes the issue by setting the touch action of the embedder to
auto in this case. A browser test is added.

Bug:  870536 
Change-Id: Id3846334510a9bf4a66a365a447f3b4d8de1ddc7
Reviewed-on: https://chromium-review.googlesource.com/1166426
Commit-Queue: Xida Chen <xidachen@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: Ehsan Karamad <ekaramad@chromium.org>
Reviewed-by: Timothy Dresser <tdresser@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583124}
[modify] https://crrev.com/ec19b70f6e22218eb829fd458dfc0435937b5377/chrome/browser/chrome_site_per_process_browsertest.cc
[modify] https://crrev.com/ec19b70f6e22218eb829fd458dfc0435937b5377/content/browser/browser_plugin/browser_plugin_guest.cc
[modify] https://crrev.com/ec19b70f6e22218eb829fd458dfc0435937b5377/content/browser/renderer_host/input/input_router_impl.cc
[modify] https://crrev.com/ec19b70f6e22218eb829fd458dfc0435937b5377/content/browser/renderer_host/input/input_router_impl.h
[modify] https://crrev.com/ec19b70f6e22218eb829fd458dfc0435937b5377/content/browser/renderer_host/input/touch_action_filter.cc
[modify] https://crrev.com/ec19b70f6e22218eb829fd458dfc0435937b5377/content/browser/web_contents/web_contents_impl.h
[modify] https://crrev.com/ec19b70f6e22218eb829fd458dfc0435937b5377/content/public/browser/web_contents.h
[modify] https://crrev.com/ec19b70f6e22218eb829fd458dfc0435937b5377/content/public/test/browser_test_utils.cc
[modify] https://crrev.com/ec19b70f6e22218eb829fd458dfc0435937b5377/content/public/test/browser_test_utils.h