Test WebGL with the passthrough command decoder on Linux.

content/test/gpu/generate_buildbot_json.py

Index: content/test/gpu/generate_buildbot_json.py
diff --git a/content/test/gpu/generate_buildbot_json.py b/content/test/gpu/generate_buildbot_json.py
index 4327074ec472d9b527911f1960234a485915d998..3a9871af2e9d453a4dbad28dd0673363900d506c 100755
--- a/content/test/gpu/generate_buildbot_json.py
+++ b/content/test/gpu/generate_buildbot_json.py
@@ -1551,6 +1551,22 @@ TELEMETRY_GPU_INTEGRATION_TESTS = {
     ],
     'asan_args': ['--is-asan'],
   },
+  'webgl_conformance_gl_passthrough': {
+    'tester_configs': [
+      {
+        # Run this on the FYI waterfall and optional tryservers.
+        'predicate': Predicates.FYI_AND_OPTIONAL,
+        'os_types': ['linux'],
+      }
+    ],
+    'target_name': 'webgl_conformance',
+    'extra_browser_args': [
+      '--use-gl=angle',
+      '--use-angle=gl',
+      '--use-passthrough-cmd-decoder',
+    ],
+    'asan_args': ['--is-asan'],
+  },
   'webgl2_conformance_tests': {
     'tester_configs': [
       {