The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cf97fd35cae7ca6fae58cff6eea2f6cc59716171

commit cf97fd35cae7ca6fae58cff6eea2f6cc59716171
Author: trchen <trchen@chromium.org>
Date: Tue Dec 13 21:53:37 2016

[Blink>Paint] Document element cannot always omit isolation

The previous assumption that nothing can be the backdrop of the document
element's stacking context was incorrect, because document background doesn't
paint as a part of the stacking context but as canvas backdrop instead.

Note that only non-composited blending elements are affected by this bug.
This CL changes behavior to match composited code path, which also matches
Firefox behavior.

BUG= 673597 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2564423003
Cr-Commit-Position: refs/heads/master@{#438298}

[modify] https://crrev.com/cf97fd35cae7ca6fae58cff6eea2f6cc59716171/third_party/WebKit/LayoutTests/TestExpectations
[modify] https://crrev.com/cf97fd35cae7ca6fae58cff6eea2f6cc59716171/third_party/WebKit/LayoutTests/css3/blending/mix-blend-mode-background-size.html
[modify] https://crrev.com/cf97fd35cae7ca6fae58cff6eea2f6cc59716171/third_party/WebKit/LayoutTests/platform/linux/css3/blending/mix-blend-mode-simple-text-expected.png
[modify] https://crrev.com/cf97fd35cae7ca6fae58cff6eea2f6cc59716171/third_party/WebKit/LayoutTests/platform/win/css3/blending/mix-blend-mode-simple-expected.png
[modify] https://crrev.com/cf97fd35cae7ca6fae58cff6eea2f6cc59716171/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/61541b08db4403da0598522067dd5950176ebbf3

commit 61541b08db4403da0598522067dd5950176ebbf3
Author: Xianzhu Wang <wangxianzhu@chromium.org>
Date: Wed Dec 21 05:34:22 2016

Auto-rebaseline for r438298

https://chromium.googlesource.com/chromium/src/+/cf97fd35ca

BUG= 673597 
TBR=trchen@chromium.org

Review-Url: https://codereview.chromium.org/2594893003 .
Cr-Commit-Position: refs/heads/master@{#440028}

[modify] https://crrev.com/61541b08db4403da0598522067dd5950176ebbf3/third_party/WebKit/LayoutTests/TestExpectations
[rename] https://crrev.com/61541b08db4403da0598522067dd5950176ebbf3/third_party/WebKit/LayoutTests/css3/blending/mix-blend-mode-simple-expected.png
[rename] https://crrev.com/61541b08db4403da0598522067dd5950176ebbf3/third_party/WebKit/LayoutTests/css3/blending/mix-blend-mode-simple-text-expected.png
[delete] https://crrev.com/6f8143d0f8714ef06bfc23130e9163c646de6e0f/third_party/WebKit/LayoutTests/platform/mac/css3/blending/mix-blend-mode-simple-expected.png
[delete] https://crrev.com/6f8143d0f8714ef06bfc23130e9163c646de6e0f/third_party/WebKit/LayoutTests/platform/mac/css3/blending/mix-blend-mode-simple-text-expected.png
[delete] https://crrev.com/6f8143d0f8714ef06bfc23130e9163c646de6e0f/third_party/WebKit/LayoutTests/platform/win/css3/blending/mix-blend-mode-simple-text-expected.png