docs: Update chromeos_debugging_tips.

The doc includes a number of isolate links, but items in isolate expire
after 90 days. So this updates these to a set of new isolate links.
Hopefully by the time these new links expire, we'll be on RDB which will
have a slightly different debugging flow.

This also adds some tips on running the tests locally.

Bug: None
Change-Id: Ib6244f787d2a914b7c3a79aaba2a33b688d346c7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2522409Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824965}

docs/testing/chromeos_debugging_tips.md

@@ -20,15 +20,22 @@ tests failing (likely in the `chrome_all_tast_tests` step), you can:
 
 - **Inspect the failed test's log snippet**: There should be a log link for
 each failed test with failure information. eg: For this [failed build], opening
-the [platform.Histograms] log link contains stack traces and error messages.
+the [ui.WindowControl] log link contains stack traces and error messages.
 
 - **View browser & system logs**: A common cause of failure on Chrome's builders
 are browser crashes. When this happens, each test's log snippets will simply
 contain warnings like "[Chrome probably crashed]". To debug these crashes,
-navigate to the test's Isolated output, most likely listed in the build under
-the test step's [shard #0 isolated out] link. From there, view the various
-`log/chrome/...` or `log/ui/...` text files and you should find some with
-browser [crashes and stack traces].
+navigate to the test's Isolated output, listed in the build under the test
+step's [shard #0 isolated out] link. There you'll find expanded logs for every
+test. For example, the [tests/ui.WindowControl/messages] log has more info
+than its earlier snippet. Additionally, you can find system logs under
+the `system_logs/` prefix. To find a system log for a particular test, match
+the timestamps printed in the test's log with the timestamps present in the
+system log filename. For instance, the previous `ui.WindowControl` failure
+matches the [system_logs/chrome/chrome_20201029-195153] browser log, which
+contains the culprit Chrome crash and backtrace.
+
+### Disabling a test
 
 There a couple ways to disable a test on Chrome's builders:
 - **With a full CrOS checkout**: If you have a full CrOS checkout, you can add
@@ -43,6 +50,21 @@ disabled tests for the step's GN target. For example, to disable a test in the
 In both cases, please make sure a bug is filed for the test, and route it to
 the appropriate owners.
 
+### Running a test locally
+
+To run a Tast test the same way it's ran on Chrome's builders:
+
+- Decide which Chrome OS device type or VM to test on.
+
+- Build Chrome via the [Simple Chrome] workflow for that board.
+
+- Deploy your Chrome to the device via the [deploy_chrome.py] tool.
+
+- Finally, run the Tast test on the device via the `cros_run_test` tool under
+  `//third_party/chromite/bin/`. eg:
+  `cros_run_test --device $DEVICE_IP --tast ui.ChromeLogin`. See [here] for more
+  info on cros_run_test.
+
 ## Telemetry
 
 >TODO: Add instructions for debugging telemetry failures.
@@ -58,10 +80,14 @@ the appropriate owners.
 
 [linux-chromeos]: https://chromium.googlesource.com/chromium/src/+/master/docs/chromeos_build_instructions.md
 [Tast]: https://chromium.googlesource.com/chromiumos/platform/tast/+/HEAD/README.md
-[failed build]: https://ci.chromium.org/p/chromium/builders/ci/chromeos-kevin-rel/14102
-[platform.Histograms]: https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8904949911599004400/+/steps/chrome_all_tast_tests_on_ChromeOS/0/logs/Deterministic_failure:_platform.Histograms__status_FAILURE_/0
+[failed build]: https://ci.chromium.org/p/chromium/builders/ci/chromeos-kevin-rel/29791
+[ui.WindowControl]: https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8865053459542681936/+/steps/chrome_all_tast_tests_on_ChromeOS/0/logs/Deterministic_failure:_ui.WindowControl__status_FAILURE_/0
 [Chrome probably crashed]: https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8905974915785988832/+/steps/chrome_all_tast_tests__retry_shards_with_patch__on_ChromeOS/0/logs/Deterministic_failure:_ui.ChromeLogin__status_FAILURE_/0
-[shard #0 isolated out]: https://isolateserver.appspot.com/browse?namespace=default-gzip&hash=fd1f6d76b076f07cc98fa7b2e0c0097f35c51cd0
-[crashes and stack traces]: https://isolateserver.appspot.com/browse?namespace=default-gzip&digest=993d58ff48bb08071d951bd8e103fa5a3c03efb1&as=chrome_20190805-044653
+[shard #0 isolated out]: https://isolateserver.appspot.com/browse?namespace=default-gzip&hash=3d35c273195f640c69b1cf0d15d19d9868e3f593
+[tests/ui.WindowControl/messages]: https://isolateserver.appspot.com/browse?namespace=default-gzip&digest=baefbcfd24c02b3ada4617d259dc6b4220b413b9&as=messages
+[system_logs/chrome/chrome_20201029-195153]: https://isolateserver.appspot.com/browse?namespace=default-gzip&digest=272166c85f190c336a9885f0267cbdea912e31da&as=chrome_20201029-195153
 [Tast attributes]: https://chromium.googlesource.com/chromiumos/platform/tast/+/HEAD/docs/test_attributes.md
 [this list]: https://codesearch.chromium.org/chromium/src/chromeos/BUILD.gn?rcl=7b0393a9091fd02edc9ae773739124f7be5a0782&l=242
+[Simple Chrome]: https://chromium.googlesource.com/chromiumos/docs/+/master/simple_chrome_workflow.md
+[deploy_chrome.py]: https://chromium.googlesource.com/chromiumos/docs/+/master/simple_chrome_workflow.md#Deploying-Chrome-to-the-device
+[here]: https://chromium.googlesource.com/chromiumos/docs/+/master/cros_vm.md#in-simple-chrome