The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c1f66677277a28a186de6251d31b77fb921f7769

commit c1f66677277a28a186de6251d31b77fb921f7769
Author: Xida Chen <xidachen@chromium.org>
Date: Fri Jan 19 06:46:11 2018

[PaintWorklet] Do null check for document paint definition

In quite a few functions in the CSSPaintImageGeneratorImpl class, we
check whether the document paint definition of a particular name exists
or not, but we never do null check on that definition. This could lead
to crash if the document paint definition is a null ptr.

This CL fixes the problem by doing null check. It also changes one
layout test to execise this code path. The change to the layout test
also fixes the problem that this layout test passes in the browser
that doesn't support paint worklet.

Bug:  802970 ,  768683 
Change-Id: Ia952ad977b63af643410b0973cc8034fac504f9f
Reviewed-on: https://chromium-review.googlesource.com/869891
Commit-Queue: Xida Chen <xidachen@chromium.org>
Reviewed-by: Robert Flack <flackr@chromium.org>
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530441}
[modify] https://crrev.com/c1f66677277a28a186de6251d31b77fb921f7769/third_party/WebKit/LayoutTests/external/wpt/css/css-paint-api/parse-input-arguments-018-ref.html
[modify] https://crrev.com/c1f66677277a28a186de6251d31b77fb921f7769/third_party/WebKit/LayoutTests/external/wpt/css/css-paint-api/parse-input-arguments-018.https.html
[modify] https://crrev.com/c1f66677277a28a186de6251d31b77fb921f7769/third_party/WebKit/Source/modules/csspaint/CSSPaintImageGeneratorImpl.cpp
[modify] https://crrev.com/c1f66677277a28a186de6251d31b77fb921f7769/third_party/WebKit/Source/modules/csspaint/CSSPaintImageGeneratorImpl.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e42bd3e8bd9f5a8033fa7c88ca3eeb94db2407a9

commit e42bd3e8bd9f5a8033fa7c88ca3eeb94db2407a9
Author: Xida Chen <xidachen@chromium.org>
Date: Tue Jan 23 18:46:25 2018

Make some css-paint-api/ tests fail on browsers that don't support PaintWorklet

Right now there are a few tests under external/wpt/css-paint-api/ that
pass no matter whether a browser supports PaintWorklet or not. The list
of these tests are here: http://wpt.fyi/css-paint-api

This CL corrects those tests and make them fail on browsers that don't
support PaintWorklet.

This CL also does a null check for the document paint definition, the null
check is exercised in parse-input-arguments-018.https.html.

Bug:  768683 
Change-Id: Ic58daf8c34505f02c1c5588120a17d8476a15536
Reviewed-on: https://chromium-review.googlesource.com/711381
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#531290}
[modify] https://crrev.com/e42bd3e8bd9f5a8033fa7c88ca3eeb94db2407a9/third_party/WebKit/LayoutTests/external/wpt/css/css-paint-api/invalid-image-constructor-error-ref.html
[modify] https://crrev.com/e42bd3e8bd9f5a8033fa7c88ca3eeb94db2407a9/third_party/WebKit/LayoutTests/external/wpt/css/css-paint-api/invalid-image-constructor-error.https.html
[modify] https://crrev.com/e42bd3e8bd9f5a8033fa7c88ca3eeb94db2407a9/third_party/WebKit/LayoutTests/external/wpt/css/css-paint-api/invalid-image-paint-error.https.html
[modify] https://crrev.com/e42bd3e8bd9f5a8033fa7c88ca3eeb94db2407a9/third_party/WebKit/LayoutTests/external/wpt/css/css-paint-api/invalid-image-pending-script.https.html

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/629ff5d659938c0fb76eede6c54d223a0334f00c

commit 629ff5d659938c0fb76eede6c54d223a0334f00c
Author: Xida Chen <xidachen@chromium.org>
Date: Wed Jan 24 14:42:42 2018

[PaintWorklet] Do null check for document paint definition

In quite a few functions in the CSSPaintImageGeneratorImpl class, we
check whether the document paint definition of a particular name exists
or not, but we never do null check on that definition. This could lead
to crash if the document paint definition is a null ptr.

This CL fixes the problem by doing null check. It also changes one
layout test to execise this code path. The change to the layout test
also fixes the problem that this layout test passes in the browser
that doesn't support paint worklet.

Bug:  802970 ,  768683 
Change-Id: Ia952ad977b63af643410b0973cc8034fac504f9f
Reviewed-on: https://chromium-review.googlesource.com/869891
Commit-Queue: Xida Chen <xidachen@chromium.org>
Reviewed-by: Robert Flack <flackr@chromium.org>
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#530441}(cherry picked from commit c1f66677277a28a186de6251d31b77fb921f7769)
Reviewed-on: https://chromium-review.googlesource.com/883763
Reviewed-by: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/branch-heads/3325@{#59}
Cr-Branched-From: bc084a8b5afa3744a74927344e304c02ae54189f-refs/heads/master@{#530369}
[modify] https://crrev.com/629ff5d659938c0fb76eede6c54d223a0334f00c/third_party/WebKit/LayoutTests/external/wpt/css/css-paint-api/parse-input-arguments-018-ref.html
[modify] https://crrev.com/629ff5d659938c0fb76eede6c54d223a0334f00c/third_party/WebKit/LayoutTests/external/wpt/css/css-paint-api/parse-input-arguments-018.https.html
[modify] https://crrev.com/629ff5d659938c0fb76eede6c54d223a0334f00c/third_party/WebKit/Source/modules/csspaint/CSSPaintImageGeneratorImpl.cpp
[modify] https://crrev.com/629ff5d659938c0fb76eede6c54d223a0334f00c/third_party/WebKit/Source/modules/csspaint/CSSPaintImageGeneratorImpl.h