Merge GPU pixel documentation

Merges various parts of the GPU Gold documentation from
gpu_pixel_testing_with_gold.md into the other parts of the GPU
documentation. Also removes references to the legacy pixel tests and
their triage process since the code for them has been removed.

Bug: 985007
Change-Id: I19d5480de77f1066046ef8fe0f076264cff01ee7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1721523
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Auto-Submit: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681868}

docs/gpu/gpu_pixel_testing_with_gold.md

 # GPU Pixel Testing With Gold
 
-This page describes in detail the GPU pixel tests that utilize Skia Gold for
-storing and comparing images (the `pixel_skia_gold_test` type). This includes
-information such as how Skia Gold works, how to triage images produced by these
-tests, and working on Gold itself.
+This page describes various extra details of the Skia Gold service
+that the GPU pixel tests use. For information on running the tests locally, see
+[this section][local pixel testing]. For common information on triaging,
+modification, or general pixel wrangling, see [GPU Pixel Wrangling] or these
+sections ([1][pixel debugging], [2][pixel updating]) of the general GPU testing
+documentation.
+
+[local pixel testing]: gpu_testing.md#Running-the-pixel-tests-locally
+[GPU Pixel Wrangling]: pixel_wrangling.md
+[pixel debugging]: gpu_testing.md#Debugging-Pixel-Test-Failures-on-the-GPU-Bots
+[pixel updating]: gpu_testing.md#Updating-and-Adding-New-Pixel-Tests-to-the-GPU-Bots
 
 [TOC]
 
@@ -111,45 +118,13 @@ the CL was merged as. In the above example, if the CL was merged as commit
 `ffff`, then both `abcd` and `abef` would be approved images on master from
 `ffff` onward.
 
-## Triaging Failures
-
-### Standard Workflow
-
-The current approach to getting the triage links for new images is:
-
-1. Navigate to the failed build.
-2. Search for the failed step for the `pixel_skia_gold_test` test.
-3. Look for either:
-    1. One or more links named `gold_triage_link for <test name>`. This will be
-    the case if there are fewer than 10 links.
-    2. A single link named
-    `Too many artifacts produced to link individually, click for links`. This
-    will be the case if there are 10 or more links.
-4. In either case, follow the link(s) to the triage page for the image the
-failing test produced.
-5. Triage images on those pages (typically by approving them, but you can also
-mark them as a negative if it is an image that should not be produced). In the
-case of a negative image, a bug should be filed on [crbug] to investigate and
-fix the cause of the that particular image being produced, as future
-occurrences of it will cause the test to fail. Such bugs should include the
-`Internals>GPU>Testing` component and whatever component is suitable for the
-type of failing test (likely `Blink>WebGL` or `Blink>Canvas`). The test should
-also be marked as failing or skipped in
-`//content/test/gpu/gpu_tests/test_expectations/pixel_expectations.txt` so that
-the test failure doesn't show up as a builder failure. If the failure is
-consistent, prefer to skip instead of mark as failing so that the failure links
-don't pile up. If the failure occurs on the trybots, include the change to the
-expectations in your CL.
-
-[crbug]: https://crbug.com
-
-In the future, a comment will also be automatically posted to CLs that produce
-new images with a link to triage them.
-
-In addition, you can see all currently untriaged images that are currently
-being produced on ToT on the [GPU Gold instance's main page][gpu gold instance]
-and currently untriaged images for a CL by substituting the Gerrit CL number
-into
+## Triaging Less Common Failures
+
+### Triaging Images Without A Specific Build
+
+You can see all currently untriaged images that are currently being produced on
+ToT on the [GPU Gold instance's main page][gpu gold instance] and currently
+untriaged images for a CL by substituting the Gerrit CL number into
 `https://chrome-gpu-gold.skia.org/search?issue=[CL Number]&unt=true&master=true`.
 
 [gpu gold instance]: https://chrome-gpu-gold.skia.org
@@ -197,38 +172,6 @@ the triage link for the problematic image.
 
 [skia crbug]: https://bugs.chromium.org/p/skia
 
-## Running Locally
-
-Normally, `goldctl` uploads images and image metadata to the Gold server when
-used. This is not desirable when running locally for a couple reasons:
-
-1. Uploading requires the user to be whitelisted on the server, and whitelisting
-everyone who wants to run the tests locally is not a viable solution.
-2. Images produced during local runs are usually slightly different from those
-that are produced on the bots due to hardware/software differences. Thus, most
-images uploaded to Gold from local runs would likely only ever actually be used
-by tests run on the machine that initially generated those images, which just
-adds noise to the list of approved images.
-
-Additionally, the tests normally rely on the Gold server for viewing images
-produced by a test run. This does not work if the data is not actually uploaded.
-
-In order to get around both of these issues, simply pass the `--local-run` flag
-to the tests. This will disable uploading, but otherwise go through the same
-steps as a test normally would. Each test will also print out a `file://` URL to
-the image it produces and a link to all approved images for that test in Gold.
-
-Because the image produced by the test locally is likely slightly different from
-any of the approved images in Gold, local test runs are likely to fail during
-the comparison step. In order to cut down on the amount of noise, you can also
-pass the `--no-skia-gold-failure` flag to not fail the test on a failed image
-comparison. When using `--no-skia-gold-failure`, you'll also need to pass the
-`--passthrough` flag in order to actually see the link output.
-
-Example usage:
-`run_gpu_integration_test.py pixel --no-skia-gold-failure --local-run
---passthrough --build-revision aabbccdd --test-machine-name local`
-
 ## Working On Gold
 
 ### Modifying Gold And goldctl

docs/gpu/pixel_wrangling.md

@@ -10,11 +10,6 @@ majority of the bots on the Chromium waterfall.
 
 [slides]: https://docs.google.com/presentation/d/1sZjyNe2apUhwr5sinRfPs7eTzH-3zO0VQ-Cj-8DlEDQ/edit?usp=sharing
 
-For information on pixel wrangling the Skia Gold version of the pixel tests
-(`pixel_skia_gold_tests` test suite), see [this documentation](gold_doc).
-
-[gold_doc]: https://chromium.googlesource.com/chromium/src/+/HEAD/docs/gpu/gpu_pixel_testing_with_gold.md
-
 [TOC]
 
 ## Fleet Status
@@ -205,24 +200,32 @@ shift, and a calendar appointment.
         main waterfalls.
 1.  Check if any pixel test failures are actual failures or need to be
     rebaselined.
-    1.  For a given build failing the pixel tests, click the "stdio" link of
-        the "pixel" step.
-    1.  The output will contain a link of the form
-        <http://chromium-browser-gpu-tests.commondatastorage.googleapis.com/view_test_results.html?242523_Linux_Release_Intel__telemetry>
-        * For pixel_skia_gold_tests the output link will be of the form
-        <https://chrome-gpu-gold.skia.org/detail?test=Pixel_BackgroundImage&digest=13c038c8d426720ae575f4cb9f0bf8da>
-    1.  Visit the link to see whether the generated or reference images look
-        incorrect.
-    1.  All of the reference images for all of the bots are stored in cloud
-        storage under [chromium-gpu-archive/reference-images]. They are indexed
-        by version number, OS, GPU vendor, GPU device, and whether or not
-        antialiasing is enabled in that configuration. You can download the
-        reference images individually to examine them in detail.
-1.  Rebaseline pixel test reference images if necessary.
-    1.  Follow the [instructions on the GPU testing page].
-    1.  Alternatively, if absolutely necessary, you can use the [Chrome
-        Internal GPU Pixel Wrangling Instructions] to delete just the broken
-        reference images for a particular configuration.
+    1. For a given build failing the pixel tests, look for either:
+        1. One or more links named `gold_triage_link for <test name>`. This will
+           be the case if there are fewer than 10 links.
+        1. A single link named
+           `Too many artifacts produced to link individually, click for links`.
+           This will be the case if there are 10 or more links.
+    1. In either case, follow the link(s) to the triage page for the image the
+       failing test produced.
+    1. Ensure you are signed in to the Gold server the links take you to (both
+       @google.com and @chromium.org accounts work).
+    1. Triage images on those pages (typically by approving them, but you can
+       mark them as negative if it is an image that should not be produced). In
+       the case of a negative image, a bug should be filed on
+       [crbug](https://crbug.com) to investigate and fix the cause of that
+       particular image being produced, as future occurrences of it will cause
+       the test to fail. Such bugs should include the `Internals>GPU>Testing`
+       component and whatever component is suitable for the type of failing
+       test (likely `Blink>WebGL` or `Blink>Canvas`). The test should also be
+       marked as failing or skipped(see the item below on updating the
+       Telemetry-based test expectations) so that the test failure doesn't show
+       up as a builder failure. If the failure is consistent, prefer to skip
+       instead of mark as failing so that the failure links don't pile up. If
+       the failure occurs on the trybots, include the change to the
+       expectations in your CL.
+    1. Additional, less common triage steps for the pixel tests can be found in
+       [this section][gold less common failures] of the GPU Gold documentation.
 1.  Update Telemetry-based test expectations if necessary.
     1.  Most of the GPU tests are run inside a full Chromium browser, launched
         by Telemetry, rather than a Gtest harness. The tests and their
@@ -260,8 +263,7 @@ https://ci.chromium.org/p/chromium/builders/luci.chromium.try/win7-rel
 [Chromium Try Flakes]: http://chromium-try-flakes.appspot.com/
 <!-- TODO(kainino): link doesn't work, but is still included from chromium-swarm homepage so not removing it now -->
 [Swarming Server Stats]: https://chromium-swarm.appspot.com/stats
-[chromium-gpu-archive/reference-images]: https://console.developers.google.com/storage/chromium-gpu-archive/reference-images
-[instructions on the GPU testing page]: https://chromium.googlesource.com/chromium/src/+/master/docs/gpu/gpu_testing.md
+[gold less common failures]: gpu_pixel_testing_with_gold.md#Triaging-Less-Common-Failures
 [Chrome Internal GPU Pixel Wrangling Instructions]: https://sites.google.com/a/google.com/client3d/documents/chrome-internal-gpu-pixel-wrangling-instructions
 [src/content/test/gpu/gpu_tests/test_expectations]: https://chromium.googlesource.com/chromium/src/+/master/content/test/gpu/gpu_tests/test_expectations
 [webgl_conformance_expectations.txt]: https://chromium.googlesource.com/chromium/src/+/master/content/test/gpu/gpu_tests/test_expectations/webgl_conformance_expectations.txt