Support test harness (text-only) tests w/o expected results.

Tools/Scripts/webkitpy/layout_tests/models/test_failures.py

Index: Tools/Scripts/webkitpy/layout_tests/models/test_failures.py
diff --git a/Tools/Scripts/webkitpy/layout_tests/models/test_failures.py b/Tools/Scripts/webkitpy/layout_tests/models/test_failures.py
index c42b79a85d8a9a6e40f4e7171f12f091b1206237..caed9204bd72e117e2a207f89a065b23df1064de 100644
--- a/Tools/Scripts/webkitpy/layout_tests/models/test_failures.py
+++ b/Tools/Scripts/webkitpy/layout_tests/models/test_failures.py
@@ -61,7 +61,8 @@ def determine_result_type(failure_list):
           FailureMissingAudio in failure_types):
         return test_expectations.MISSING
     else:
-        is_text_failure = FailureTextMismatch in failure_types
+        is_text_failure = (FailureTextMismatch in failure_types or
+                           FailureTestHarnessAssertion in failure_types)
         is_image_failure = (FailureImageHashIncorrect in failure_types or
                             FailureImageHashMismatch in failure_types)
         is_audio_failure = (FailureAudioMismatch in failure_types)
@@ -141,10 +142,16 @@ class FailureMissingResult(TestFailure):
         return "-expected.txt was missing"
 
 
+class FailureTestHarnessAssertion(TestFailure):
+    def message(self):
+        return "asserts failed"
+
+
 class FailureTextMismatch(TestFailure):
     def message(self):
         return "text diff"
 
+
 class FailureMissingImageHash(TestFailure):
     def message(self):
         return "-expected.png was missing an embedded checksum"
@@ -210,6 +217,7 @@ class FailureEarlyExit(TestFailure):
 # Convenient collection of all failure classes for anything that might
 # need to enumerate over them all.
 ALL_FAILURE_CLASSES = (FailureTimeout, FailureCrash, FailureMissingResult,
+                       FailureTestHarnessAssertion,
                        FailureTextMismatch, FailureMissingImageHash,
                        FailureMissingImage, FailureImageHashMismatch,
                        FailureImageHashIncorrect, FailureReftestMismatch,