Kill AddError/AddErrorMessage from PageTestResults.

content/test/gpu/gpu_tests/webgl_conformance.py

Index: content/test/gpu/gpu_tests/webgl_conformance.py
diff --git a/content/test/gpu/gpu_tests/webgl_conformance.py b/content/test/gpu/gpu_tests/webgl_conformance.py
index 8deaf7ed0dc2bb5629fec956f17d5d518601fdf6..b09282d7a7252aa4109a951fa77b186ae3c78fee 100644
--- a/content/test/gpu/gpu_tests/webgl_conformance.py
+++ b/content/test/gpu/gpu_tests/webgl_conformance.py
@@ -69,7 +69,7 @@ def _WebGLTestMessages(tab):
 
 class WebglConformanceValidator(page_test.PageTest):
   def __init__(self):
-    super(WebglConformanceValidator, self).__init__(attempts=1, max_errors=10)

[Ken Russell (switch to Gerrit), 2014/07/15 00:20:20]

What's the side-effect of this change? The maximum number of failures should be
clamped to 10, too, in order to prevent runaway test runs if somebody breaks
something badly in one of their try jobs, and each failure would for whatever
reason have a really long timeout.

[nduca, 2014/07/15 02:03:28]

is it important to distinguish between errors and failures for your logic?

[Ken Russell (switch to Gerrit), 2014/07/15 04:42:18]

No (Brandon, Mo, correct me if I'm wrong), but it is important to abort runs
that are failing lots of tests.

[chrishenry, 2014/07/15 17:55:52]

Previously this test doesn't clamp down on number of failures, only errors. I
added max_failures=10 to this call, so it'll now clamp down on failures too.

+    super(WebglConformanceValidator, self).__init__(attempts=1)
 
   def ValidatePage(self, page, tab, results):
     if not _DidWebGLTestSucceed(tab):