If failed in

https://build.chromium.org/p/chromium.linux/builders/Cast%20Linux/builds/44056
https://build.chromium.org/p/chromium.linux/builders/Cast%20Linux/builds/44057
https://build.chromium.org/p/chromium.linux/builders/Cast%20Linux/builds/44067

the log is the same in all 3 red builds:

=======
[ RUN      ] DumpAccessibilityTreeTest.AccessibilityIframeTransformCrossProcess
DevTools listening on ws://127.0.0.1:53459/devtools/browser/2e880c7e-e8b9-4508-b3d8-21642c383db9
[12539:12539:0919/210538.604157:1881983170:INFO:dump_accessibility_browsertest_base.cc(234)] Testing: /mnt/data/b/c/b/Cast_Linux/src/content/test/data/accessibility/html/iframe-transform-cross-process.html
[12539:12539:0919/210538.604198:1881983205:INFO:dump_accessibility_browsertest_base.cc(236)] Expected output: /mnt/data/b/c/b/Cast_Linux/src/content/test/data/accessibility/html/iframe-transform-cross-process-expected-blink.txt
[12539:12539:0919/210538.721695:1882100704:WARNING:render_frame_host_impl.cc(2669)] OnDidStopLoading was called twice.
[12539:12539:0919/210538.722267:1882101276:WARNING:render_frame_host_impl.cc(2669)] OnDidStopLoading was called twice.
../../content/browser/accessibility/dump_accessibility_browsertest_base.cc:365: Failure
Value of: is_different
  Actual: true
Expected: false
[12539:12539:0919/210538.723376:1882102384:ERROR:dump_accessibility_browsertest_base.cc(390)] Diff:
* Line Expected
- ---- --------
     1 rootWebArea pageLocation=(0, 0)
     2 ++iframe pageLocation=(0, 0)
     3 ++++rootWebArea pageLocation=(0, 0)
*    4 ++++++image pageLocation=(10, 10) pageSize=(200, 200)
     5 ++iframe pageLocation=(0, 250) transform
*    6 ++++rootWebArea pageLocation=(0, 250)
*    7 ++++++image pageLocation=(15, 265) pageSize=(300, 300)
     8 <-- End-of-file -->
Actual
------
rootWebArea pageLocation=(0, 0)
++iframe pageLocation=(0, 0)
++++rootWebArea pageLocation=(0, 0)
++++++image pageLocation=(0, 0)
++iframe pageLocation=(0, 250) transform
++++rootWebArea pageLocation=(0, 248)
++++++image pageLocation=(0, 248)
<-- End-of-file -->
[12539:12539:0919/210538.734234:1882113244:INFO:dump_accessibility_browsertest_base.cc(219)] File not found: /mnt/data/b/c/b/Cast_Linux/src/content/test/data/accessibility/html/iframe-transform-cross-process
[12539:12539:0919/210538.734261:1882113268:INFO:dump_accessibility_browsertest_base.cc(220)] No expectation file present, ignoring test on this platform. To run this test anyway, create /mnt/data/b/c/b/Cast_Linux/src/content/test/data/accessibility/html/iframe-transform-cross-process (it can be empty) and then run content_browsertests with the switch: --generate-accessibility-test-expectations
[  FAILED  ] DumpAccessibilityTreeTest.AccessibilityIframeTransformCrossProcess, where TypeParam =  and GetParam() =  (234 ms)
[262/2073] DumpAccessibilityTreeTest.AccessibilityIframeTransformCrossProcess (258 ms)
======

I don't see any related CL in https://build.chromium.org/p/chromium.linux/builders/Cast%20Linux/builds/44056.

The test is based on iframe-transform-cross-process.html, which was touched in https://chromium-review.googlesource.com/c/chromium/src/+/669949 recently.

katydek@, could your CL be related?

meanwhile, I will disable the test.

I am disabling the test in https://chromium-review.googlesource.com/c/chromium/src/+/674937.

dmazzoni@, could you redirect please?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3ec10d4a0dbd347df011c97f9f6b637dee0750d4

commit 3ec10d4a0dbd347df011c97f9f6b637dee0750d4
Author: Vitalii Iarko <vitaliii@chromium.org>
Date: Wed Sep 20 15:28:19 2017

Disable DumpAccessibilityTreeTest.AccessibilityIframeTransformCrossProcess.

On Linux, because it is flaky.

TBR: dmazzoni@chromium.org
Bug:  767032 
Change-Id: Ief0a276bf1d5925f345c8045bd4f95d553c7ac11
Reviewed-on: https://chromium-review.googlesource.com/674937
Reviewed-by: vitaliii <vitaliii@chromium.org>
Commit-Queue: vitaliii <vitaliii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#503149}
[modify] https://crrev.com/3ec10d4a0dbd347df011c97f9f6b637dee0750d4/content/browser/accessibility/dump_accessibility_tree_browsertest.cc

Hopefully https://chromium-review.googlesource.com/c/chromium/src/+/675763 will reduce the flakyness here and in a similar test.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/831fa9721ed4f94c9073fe79135707e32d8a6fad

commit 831fa9721ed4f94c9073fe79135707e32d8a6fad
Author: Katie Dektar <katydek@google.com>
Date: Wed Sep 20 21:28:01 2017

Wait for all root web areas to have non-zero size in tests.

This should reduce flakyness in iframe tests. Re-enable flaky test.

Bug:  767032 
Change-Id: Ied5d03a323bddac86389b0052777fc2a7422cb5b
Reviewed-on: https://chromium-review.googlesource.com/675763
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Katie Dektar <katydek@google.com>
Cr-Commit-Position: refs/heads/master@{#503253}
[modify] https://crrev.com/831fa9721ed4f94c9073fe79135707e32d8a6fad/content/browser/accessibility/dump_accessibility_browsertest_base.cc
[modify] https://crrev.com/831fa9721ed4f94c9073fe79135707e32d8a6fad/content/browser/accessibility/dump_accessibility_tree_browsertest.cc