I talked to senorblanco@ about it and neither of us have any idea why my change would have affected this test, let alone why it'd cause flakiness. Since it's still running on other platforms it's probably fine to leave for now.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e4cc2032a746a37405bf010f36f5a1caf741e05a

commit e4cc2032a746a37405bf010f36f5a1caf741e05a
Author: schenney <schenney@chromium.org>
Date: Wed Sep 14 15:07:54 2016

Rebaseline svg/filters/filter-source-position.svg

The test was considered flakey, but now it's always failing. Get
some new baselines to figure out if it's actually flakey.

TBR=senorblanco@chromium.org
BUG= 627782 

Review-Url: https://codereview.chromium.org/2332933002
Cr-Commit-Position: refs/heads/master@{#418565}

[modify] https://crrev.com/e4cc2032a746a37405bf010f36f5a1caf741e05a/third_party/WebKit/LayoutTests/TestExpectations
[add] https://crrev.com/e4cc2032a746a37405bf010f36f5a1caf741e05a/third_party/WebKit/LayoutTests/platform/linux/svg/filters/filter-source-position-expected.png
[modify] https://crrev.com/e4cc2032a746a37405bf010f36f5a1caf741e05a/third_party/WebKit/LayoutTests/platform/win/svg/filters/filter-source-position-expected.png
[delete] https://crrev.com/96716fccb60b7c061269bf35b2bf52589c379925/third_party/WebKit/LayoutTests/platform/win7/svg/filters/filter-source-position-expected.png