Fix GPU volteer pixel tests

Fixes the GPU pixel tests on volteer being unable to interact with Gold
due to authentication issues.

Bug: 1502617
Change-Id: Ia816237a2f32167c54446a0761b6e02040c26b46
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5054115
Auto-Submit: Brian Sheedy <[email protected]>
Reviewed-by: Yuly Novikov <[email protected]>
Commit-Queue: Brian Sheedy <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1229440}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index d50812c..cd90eb6 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -2576,6 +2576,17 @@
       },
     },
   },
+  'expected_color_pixel_passthrough_test VOLTEER_PUBLIC_RELEASE_LKGM': {
+    'modifications': {
+      'ChromeOS FYI Release Skylab (volteer)': {
+        'args': [
+          # Skylab currently doesn't support use of LUCI_CONTEXT, so Gold cannot
+          # automatically get the service account to authenticate with.
+          '--service-account=/creds/service_accounts/skylab-drone.json',
+        ],
+      },
+    },
+  },
   'expected_color_pixel_validating_test': {
     'modifications': {
       'Android FYI Release (Pixel 4)': {
@@ -3850,6 +3861,17 @@
       },
     },
   },
+  'pixel_skia_gold_passthrough_test VOLTEER_PUBLIC_RELEASE_LKGM': {
+    'modifications': {
+      'ChromeOS FYI Release Skylab (volteer)': {
+        'args': [
+          # Skylab currently doesn't support use of LUCI_CONTEXT, so Gold cannot
+          # automatically get the service account to authenticate with.
+          '--service-account=/creds/service_accounts/skylab-drone.json',
+        ],
+      },
+    },
+  },
   'pixel_skia_gold_validating_test': {
     'modifications': {
       'Android FYI Release (Pixel 4)': {