The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a32d7da36f7be01d549617b540f8622f76b88e3a

commit a32d7da36f7be01d549617b540f8622f76b88e3a
Author: W. James MacLean <wjmaclean@chromium.org>
Date: Fri Jan 18 19:01:38 2019

Allow looser observer tolerance for final page scale factor in test.

The synthetic pinch gesture mechanism used in
SitePerProcessBrowserTest.PageScaleFactorPropagatesToOOPIFs is known to
undershoot its target (https://crbug.com/469947), and it appears to do
so in an inconsistent manner (sometimes we achieve 5% tolerance,
sometimes it's more like 10%).

This CL loosens the tolerance until a resolution is found for 469947.

TBR=avi@chromium.org

Bug: 469947, 923226
Change-Id: I2169c9e516aefa95c86ff5757309c7c24347d05c
Reviewed-on: https://chromium-review.googlesource.com/c/1422419
Commit-Queue: James MacLean <wjmaclean@chromium.org>
Auto-Submit: James MacLean <wjmaclean@chromium.org>
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624223}
[modify] https://crrev.com/a32d7da36f7be01d549617b540f8622f76b88e3a/content/browser/site_per_process_browsertest.cc