Maybe CL https://chromium-review.googlesource.com/1190625 is the cause

Since https://ci.chromium.org/buildbot/chromium.webkit/WebKit%20Linux%20Trusty%20Leak/23587

The following Layout test are failing on Linux:
Unexpected Failures:
* virtual/layout_ng/external/wpt/css/CSS2/floats-clear/floats-005.xht
* virtual/layout_ng/external/wpt/css/CSS2/floats-clear/floats-136.xht
* virtual/layout_ng/external/wpt/css/CSS2/linebox/inline-formatting-context-022.xht
* virtual/layout_ng/fast/inline/drawStyledEmptyInlines.html
* virtual/layout_ng/fast/inline/drawStyledEmptyInlinesWithWS.html
* virtual/layout_ng/fast/inline/inline-box-background-long-image.html
* virtual/layout_ng/fast/inline/inline-box-background-repeat-x.html
* virtual/layout_ng/fast/inline/inline-box-background-repeat-y.html
* virtual/layout_ng/fast/inline/inline-box-background.html
* virtual/layout_ng/fast/writing-mode/background-vertical-lr.html
* virtual/layout_ng/fast/writing-mode/background-vertical-rl.html
* virtual/layout_ng/fast/writing-mode/border-image-vertical-lr.html
* virtual/layout_ng/fast/writing-mode/border-image-vertical-rl.html
* virtual/layout_ng_experimental/external/wpt/css/css-multicol/multicol-fill-auto-003.xht