Several builders fail due with this message (usually on single shards):
"Command line too long for RegisterApplicationRestart"

Avery recent failure (although I am not sure this is limited to Windows were the browser_tests failing on chromium.win/Win7 Tests (dbg)(1)

Builders failed on Win7 Tests (dbg)(1): https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29

The failing build was https://uberchromegw.corp.google.com/i/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29/builds/63879

The full error message was (repeatedly):
[ RUN      ] PolicyToolUITest.SessionTypeValidation
[5612:4696:1012/071512.717:WARNING:chrome_browser_main_win.cc(610)] Command line too long for RegisterApplicationRestart:  --brave-new-test-launcher --cfi-diag=0 --gtest_also_run_disabled_tests --gtest_filter=PolicyToolUITest.SessionTypeValidation --single_process --test-launcher-bot-mode --test-launcher-output="C:\Users\CHROME~2\AppData\Local\Temp\scoped_dir7148_689\results7148_22018\test_results.xml" --test-launcher-summary-output="e:\b\s\w\iotrjhk_\output.json" --user-data-dir="C:\Users\CHROME~2\AppData\Local\Temp\scoped_dir7148_689\d7148_20810" --disable-offline-auto-reload --no-first-run --no-default-browser-check --enable-logging=stderr --safebrowsing-disable-auto-update --disable-default-apps --wm-window-animations-disabled --disable-component-update --test-type=browser --force-color-profile=srgb --disable-zero-browsers-open-for-tests --ipc-connection-timeout=45 --allow-file-access-from-files --dom-automation --log-gpu-control-list-decisions --disable-backgrounding-occluded-windows --disable-gl-drawing-for-tests --override-use-software-gl-for-tests --force-color-profile=srgb --enable-features=PolicyTool --disable-features=NetworkPrediction --flag-switches-begin --flag-switches-end --restore-last-session about:blank
[3200:2588:1012/071513.196:ERROR:direct_composition_surface_win.cc(1094)] Failing to detect HDR, couldn't retrieve D3D11 device from ANGLE.
[3200:2588:1012/071513.227:INFO:media_foundation_video_encode_accelerator_win.cc(340)] Windows versions earlier than 8 are not supported.
[4060:2308:1012/071515.817:ERROR:render_process_impl.cc(193)] WebFrame LEAKED 1 TIMES
[5612:7752:1012/071515.863:ERROR:process_win.cc(139)] Unable to terminate process: Access is denied. (0x5)

Notably: the parameter count is equal and only the user-data-dir changed.

CC'ed Policy folks: This issue affects your tests a little bit more frequently and I saw a revert fly by that actually tried to fix this but apparently hasn't succeeded. Do you know where to start?
 

Several builders fail due with this message (usually on single shards):
"Command line too long for RegisterApplicationRestart"

Avery recent failure (although I am not sure this is limited to Windows were the browser_tests failing on chromium.win/Win7 Tests (dbg)(1)

Builders failed on Win7 Tests (dbg)(1): https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29

The failing build was https://uberchromegw.corp.google.com/i/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29/builds/63879

The full error message was (repeatedly):
[ RUN      ] PolicyToolUITest.SessionTypeValidation
[5612:4696:1012/071512.717:WARNING:chrome_browser_main_win.cc(610)] Command line too long for RegisterApplicationRestart:  --brave-new-test-launcher --cfi-diag=0 --gtest_also_run_disabled_tests --gtest_filter=PolicyToolUITest.SessionTypeValidation --single_process --test-launcher-bot-mode --test-launcher-output="C:\Users\CHROME~2\AppData\Local\Temp\scoped_dir7148_689\results7148_22018\test_results.xml" --test-launcher-summary-output="e:\b\s\w\iotrjhk_\output.json" --user-data-dir="C:\Users\CHROME~2\AppData\Local\Temp\scoped_dir7148_689\d7148_20810" --disable-offline-auto-reload --no-first-run --no-default-browser-check --enable-logging=stderr --safebrowsing-disable-auto-update --disable-default-apps --wm-window-animations-disabled --disable-component-update --test-type=browser --force-color-profile=srgb --disable-zero-browsers-open-for-tests --ipc-connection-timeout=45 --allow-file-access-from-files --dom-automation --log-gpu-control-list-decisions --disable-backgrounding-occluded-windows --disable-gl-drawing-for-tests --override-use-software-gl-for-tests --force-color-profile=srgb --enable-features=PolicyTool --disable-features=NetworkPrediction --flag-switches-begin --flag-switches-end --restore-last-session about:blank
[3200:2588:1012/071513.196:ERROR:direct_composition_surface_win.cc(1094)] Failing to detect HDR, couldn't retrieve D3D11 device from ANGLE.
[3200:2588:1012/071513.227:INFO:media_foundation_video_encode_accelerator_win.cc(340)] Windows versions earlier than 8 are not supported.
[4060:2308:1012/071515.817:ERROR:render_process_impl.cc(193)] WebFrame LEAKED 1 TIMES
[5612:7752:1012/071515.863:ERROR:process_win.cc(139)] Unable to terminate process: Access is denied. (0x5)

Notably: the parameter count is equal and only the user-data-dir changed.

CC'ed Policy folks: This issue affects your tests a little bit more frequently and I saw a revert fly by [1] that tries to fix this but not sure it addresses the underlying cause. Do you know where to start?

[1] https://chromium-review.googlesource.com/690237