https://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=fast%2Frepaint%2Fobscured-background-no-repaint.html&testType=webkit_tests

It's also flaky on Win7 (dbg).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7fb3008d99886e6b5ae831f9daeb8a5e7d0fac11

commit 7fb3008d99886e6b5ae831f9daeb8a5e7d0fac11
Author: Xianzhu Wang <wangxianzhu@chromium.org>
Date: Wed Jun 22 17:12:43 2016

fast/repaint/obscured-background-no-repaint.html is flaky on Linux/Win dbg

BUG= 622368 

Review URL: https://codereview.chromium.org/2090103002 .

Cr-Commit-Position: refs/heads/master@{#401322}

[modify] https://crrev.com/7fb3008d99886e6b5ae831f9daeb8a5e7d0fac11/third_party/WebKit/LayoutTests/TestExpectations

The underlying problem is not new, but is exposed by recent change of repaint tests.

When an animated gif changes, we don't check if the image is obscured and setShouldDoFullPaintInvalidation().

I think the test passes on release build and passed on debug build because it finishes quickly before any chance of the animated gif changes frame. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/566630696e9689b3fb7a2cdf3aad855efb3d39ad

commit 566630696e9689b3fb7a2cdf3aad855efb3d39ad
Author: wangxianzhu <wangxianzhu@chromium.org>
Date: Tue Aug 09 16:10:12 2016

Separate backgroundObscurationStatus and hasBoxDecorationBackground

Background obscuration status is for background only, not for other
box decoration backgrounds (e.g. border, shadow).

BUG= 622368 

Review-Url: https://codereview.chromium.org/2225033003
Cr-Commit-Position: refs/heads/master@{#410693}

[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/layout/LayoutBox.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.h
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/layout/LayoutBoxTest.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/layout/LayoutImage.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/layout/LayoutObject.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/layout/LayoutObject.h
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/paint/BoxPainter.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/paint/TableCellPainter.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/paint/TableRowPainter.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/paint/TableSectionPainter.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/paint/ThemePainterDefault.cpp
[modify] https://crrev.com/566630696e9689b3fb7a2cdf3aad855efb3d39ad/third_party/WebKit/Source/core/style/ComputedStyle.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3646f9d8a418eabf1e7d8cb29ca446382848e04c

commit 3646f9d8a418eabf1e7d8cb29ca446382848e04c
Author: wangxianzhu <wangxianzhu@chromium.org>
Date: Thu Aug 11 15:35:40 2016

Don't invalidate paint on background image change if it's obscured

BUG= 622368 
TEST=fast/repaint/obscured-background-no-repaint.html

Review-Url: https://codereview.chromium.org/2229643002
Cr-Commit-Position: refs/heads/master@{#411337}

[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/LayoutTests/fast/repaint/obscured-background-no-repaint-expected.txt
[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/LayoutTests/fast/repaint/obscured-background-no-repaint.html
[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/LayoutTests/fast/shapes/shape-outside-floats/shape-outside-insert-svg-shape-expected.html
[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/LayoutTests/fast/shapes/shape-outside-floats/shape-outside-insert-svg-shape.html
[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/Source/core/layout/LayoutBox.cpp
[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/Source/core/layout/LayoutBox.h
[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/Source/core/layout/LayoutImage.cpp
[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/Source/core/layout/LayoutObject.cpp
[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/Source/core/layout/LayoutObject.h
[modify] https://crrev.com/3646f9d8a418eabf1e7d8cb29ca446382848e04c/third_party/WebKit/Source/platform/graphics/BitmapImage.cpp