Example Stack Trace:

../../chrome/browser/ui/views/frame/browser_view_browsertest.cc:417: Failure
Expected equality of these values:
  ui::AXPlatformNodeTestHelper::FindChildByName(ax_node, "Reload")
    Which is: 0x7ff1c500faa0
  nullptr
    Which is: (nullptr)
Stack trace:
0   libbase.dylib                       0x00000001323e7afc base::debug::StackTrace::StackTrace() + 28
1   browser_tests                       0x000000011304678a StackTraceGetter::CurrentStackTrace(int, int) + 90
2   browser_tests                       0x000000011306a887 testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop(int) + 71
3   browser_tests                       0x0000000113069bfb testing::internal::AssertHelper::operator=(testing::Message const&) const + 139
4   browser_tests                       0x000000011284c33b BrowserViewTest_GetAccessibleTabModalDialogTree_Test::RunTestOnMainThread() + 1547
5   browser_tests                       0x0000000117ea2d54 content::BrowserTestBase::ProxyRunTestOnMainThreadLoop() + 2116
6   browser_tests                       0x0000000117ea59ad void base::internal::FunctorTraits<void (content::BrowserTestBase::*)(), void>::Invoke<void (content::BrowserTestBase::*)(), content::BrowserTestBase*>(void (content::BrowserTestBase::*)(), content::BrowserTestBase*&&) + 125
7   browser_tests                       0x0000000117ea58f4 void base::internal::InvokeHelper<false, void>::MakeItSo<void (content::BrowserTestBase::* const&)(), content::BrowserTestBase*>(void (content::BrowserTestBase::* const&&&)(), content::BrowserTestBase*&&) + 68
8   browser_tests                       0x0000000117ea5883 void base::internal::Invoker<base::internal::BindState<void (content::BrowserTestBase::*)(), base::internal::UnretainedWrapper<content::BrowserTestBase> >, void ()>::RunImpl<void (content::BrowserTestBase::* const&)(), std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserTestBase> > const&, 0ul>(void (content::BrowserTestBase::* const&&&)(), std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserTestBase> > const&&&, std::__1::integer_sequence<unsigned long, 0ul>) + 99
9   browser_tests                       0x0000000117ea57ac base::internal::Invoker<base::internal::BindState<void (content::BrowserTestBase::*)(), base::internal::UnretainedWrapper<content::BrowserTestBase> >, void ()>::Run(base::internal::BindStateBase*) + 44
10  browser_tests                       0x000000010ffcc7ed base::RepeatingCallback<void ()>::Run() const & + 61
11  browser_tests                       0x0000000116359a42 ChromeBrowserMainParts::PreMainMessageLoopRunImpl() + 8594
12  browser_tests                       0x00000001163577fa ChromeBrowserMainParts::PreMainMessageLoopRun() + 250
13  libcontent.dylib                    0x000000013f306d81 content::BrowserMainLoop::PreMainMessageLoopRun() + 337
14  libcontent.dylib                    0x000000013f30d67d int base::internal::FunctorTraits<int (content::BrowserMainLoop::*)(), void>::Invoke<int (content::BrowserMainLoop::*)(), content::BrowserMainLoop*>(int (content::BrowserMainLoop::*)(), content::BrowserMainLoop*&&) + 125
15  libcontent.dylib                    0x000000013f30d5c4 int base::internal::InvokeHelper<false, int>::MakeItSo<int (content::BrowserMainLoop::* const&)(), content::BrowserMainLoop*>(int (content::BrowserMainLoop::* const&&&)(), content::BrowserMainLoop*&&) + 68
16  libcontent.dylib                    0x000000013f30d553 int base::internal::Invoker<base::internal::BindState<int (content::BrowserMainLoop::*)(), base::internal::UnretainedWrapper<content::BrowserMainLoop> >, int ()>::RunImpl<int (content::BrowserMainLoop::* const&)(), std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserMainLoop> > const&, 0ul>(int (content::BrowserMainLoop::* const&&&)(), std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserMainLoop> > const&&&, std::__1::integer_sequence<unsigned long, 0ul>) + 99
17  libcontent.dylib                    0x000000013f30d44c base::internal::Invoker<base::internal::BindState<int (content::BrowserMainLoop::*)(), base::internal::UnretainedWrapper<content::BrowserMainLoop> >, int ()>::Run(base::internal::BindStateBase*) + 44
18  libcontent.dylib                    0x000000013ff099ed base::RepeatingCallback<int ()>::Run() const & + 61
19  libcontent.dylib                    0x0000000140960620 content::StartupTaskRunner::RunAllTasksNow() + 528
20  libcontent.dylib                    0x000000013f301e91 content::BrowserMainLoop::CreateStartupTasks() + 2769
21  libcontent.dylib                    0x000000013f3113ee content::BrowserMainRunnerImpl::Initialize(content::MainFunctionParams const&) + 2430
22  libcontent.dylib                    0x000000013f2f9396 content::BrowserMain(content::MainFunctionParams const&) + 550
23  libcontent.dylib                    0x000000014237d515 content::RunBrowserProcessMain(content::MainFunctionParams const&, content::ContentMainDelegate*) + 309
24  libcontent.dylib                    0x000000014238097e content::ContentMainRunnerImpl::Run(bool) + 4318
25  libcontent.dylib                    0x000000014237757c content::ContentServiceManagerMainDelegate::RunEmbedderProcess() + 76
26  libembedder.dylib                   0x0000000154b743d9 service_manager::Main(service_manager::MainParams const&) + 3753
27  libcontent.dylib                    0x000000014237d399 content::ContentMain(content::ContentMainParams const&) + 89
28  browser_tests                       0x0000000117ea2191 content::BrowserTestBase::SetUp() + 8385
29  browser_tests                       0x0000000116106831 InProcessBrowserTest::SetUp() + 2673


Test got introduced in r588142, will revert.

Reverting r588142 in https://crrev.com/c/1201824; adding original CL author.

jamwalla@, please investigate.

 Issue 879813  has been merged into this issue.

bugdroid is off - crrev.com/c/1204710 landed as https://chromium.googlesource.com/chromium/src/+/4829f738bb1b9028c0f325966e0143316bf8596d

the test is disabled on Mac, since tab modal dialogs are treated as native windows.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4829f738bb1b9028c0f325966e0143316bf8596d

commit 4829f738bb1b9028c0f325966e0143316bf8596d
Author: James Wallace-Lee <jamwalla@chromium.org>
Date: Tue Sep 04 22:34:04 2018

Reland "a11y: hide the rest of the browser when a tab-modal dialog is present"

This is a reland of 9ce4948885ea3718cb2e8d150da06deb9911deef

The test, GetAccessibleTabModalDialogTree, failed on OSX because
tab-modal dialogs are treated as native windows in Voiceover.
This fix is unnecessary on OSX so the test is now disabled there.
(See also crrev.com/c/1197333)

Original change's description:
> a11y: hide the rest of the browser when a tab-modal dialog is present
>
> When a tab-modal dialog is shown, the page underneath it is inert. But
> NVDA reads the page underneath the dialog when users press Insert+B to
> read the whole dialog. To fix this, we hide the rest of the browser
> from the accessibility tree when a tab-modal dialog is visible by
> modifying AXPlatformNodeDelegate::PopulateChildWidgetVector to return
> only the dialog.
>
> Bug:  775680 
> Change-Id: I2a5ec2eeef5ffe50ebd8819836c89ae73ddfdd36
> Reviewed-on: https://chromium-review.googlesource.com/1189054
> Commit-Queue: James Wallace-Lee <jamwalla@chromium.org>
> Reviewed-by: Scott Violet <sky@chromium.org>
> Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#588142}

Bug:  775680 ,  879995 
Change-Id: Ie9d49eb5e67655e98ab220c8fc78e56aaf346cd0
Reviewed-on: https://chromium-review.googlesource.com/1204710
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: James Wallace-Lee <jamwalla@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588671}
[modify] https://crrev.com/4829f738bb1b9028c0f325966e0143316bf8596d/chrome/browser/ui/views/frame/browser_view_browsertest.cc
[modify] https://crrev.com/4829f738bb1b9028c0f325966e0143316bf8596d/ui/accessibility/BUILD.gn
[add] https://crrev.com/4829f738bb1b9028c0f325966e0143316bf8596d/ui/accessibility/platform/ax_platform_node_test_helper.cc
[add] https://crrev.com/4829f738bb1b9028c0f325966e0143316bf8596d/ui/accessibility/platform/ax_platform_node_test_helper.h
[modify] https://crrev.com/4829f738bb1b9028c0f325966e0143316bf8596d/ui/views/accessibility/view_ax_platform_node_delegate.cc
[modify] https://crrev.com/4829f738bb1b9028c0f325966e0143316bf8596d/ui/views/accessibility/view_ax_platform_node_delegate.h