On Pixel C, suppress WebGL test failures and stop running gl_tests for now.

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 fdafb7cfa855d63e901db85b35d765e2822eea6a..6505db9e8e4e1c4aae8fa491ef86a92ad178bffc 100755
--- a/content/test/gpu/generate_buildbot_json.py
+++ b/content/test/gpu/generate_buildbot_json.py
@@ -671,6 +671,15 @@ COMMON_GTESTS = {
         'allow_on_android': True,
       }
     ],
+    'disabled_tester_configs': [
+      {
+        'names': [
+          # TODO(kbr): investigate inability to recognize this
+          # configuration in the various tests. crbug.com/624621
+          'Android Release (Pixel C)',
+        ],
+      },
+    ],
     'desktop_args': ['--use-gpu-in-tests']
   },
   'gl_unittests': {