(Reland) Port WebGL extension availability tests to the integration test harness.

content/test/gpu/gpu_tests/gpu_integration_test.py

Index: content/test/gpu/gpu_tests/gpu_integration_test.py
diff --git a/content/test/gpu/gpu_tests/gpu_integration_test.py b/content/test/gpu/gpu_tests/gpu_integration_test.py
index 4ad6af24708143a9344431a6f67645db5bbf6945..75df3cbaec20bc4786ad851953674e8940781cc6 100644
--- a/content/test/gpu/gpu_tests/gpu_integration_test.py
+++ b/content/test/gpu/gpu_tests/gpu_integration_test.py
@@ -68,6 +68,12 @@ class GpuIntegrationTest(
       # aborts the control flow here.
       self.skipTest('SKIPPING TEST due to test expectations')
     try:
+      # TODO(nednguyen): For some reason the arguments are getting wrapped
+      # in another tuple sometimes (like in the WebGL extension tests).
+      # Perhaps only if multiple arguments are yielded in the test
+      # generator?
+      if len(args) == 1 and isinstance(args[0], tuple):
+        args = args[0]
       self.RunActualGpuTest(url, *args)
     except Exception:
       if expectation == 'pass':