Revert of Consider any testharness result with >= 1 PASS and no FAIL to be passing.

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/models/testharness_results.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Utility module for checking testharness test output."""
 
 _TESTHARNESSREPORT_HEADER = 'This is a testharness.js-based test.'
 _TESTHARNESSREPORT_FOOTER = 'Harness: the test ran to completion.'
 
 
@@ skipping 16 matching lines @@
     for line in lines:
         if line == _TESTHARNESSREPORT_HEADER:
             found_header = True
         elif line == _TESTHARNESSREPORT_FOOTER:
             found_footer = True
 
     return found_header and found_footer
 
 
 def is_testharness_output_passing(content_text):
-    """Checks whether |content_text| is a passing testharness output.
+    """Returns whether |content_text| is a passing testharness output."""
 
-    Under a relatively loose/accepting definition of passing
-    testharness output, we consider any output with at least one
-    PASS result and no FAIL result (or TIMEOUT or NOTRUN).
-    """
-    # Leading and trailing whitespace are ignored.
+    # Leading and trailing white spaces are accepted.
     lines = content_text.strip().splitlines()
     lines = [line.strip() for line in lines]
 
-    at_least_one_pass = False
+    # The check is very conservative and rejects any unexpected content in the output.
+    previous_line_is_console_line = False
+    for line in lines:
+        # There should be no empty lines, unless the empty line follows a console message.
+        if len(line) == 0:
+            if previous_line_is_console_line:
+                continue
+            else:
+                return False
 
-    for line in lines:
+        # Those lines are expected to be exactly equivalent.
+        if line == _TESTHARNESSREPORT_HEADER or line == _TESTHARNESSREPORT_FOOTER:
+            previous_line_is_console_line = False
+            continue
+
+        # Those are expected passing output.
+        if line.startswith('CONSOLE'):
+            previous_line_is_console_line = True
+            continue
+
         if line.startswith('PASS'):
-            at_least_one_pass = True
+            previous_line_is_console_line = False
             continue
+
+        # Those are expected failing output.
         if (line.startswith('FAIL') or
                 line.startswith('TIMEOUT') or
                 line.startswith('NOTRUN') or
                 line.startswith('Harness Error. harness_status = ')):
             return False
 
-    return at_least_one_pass
+        # Unexpected output should be considered as a failure.
+        return False
+
+    return True
 
 
 def has_console_errors_or_warnings(content_text):
     """Returns whether |content_text| is has console errors or warnings."""
 
     def is_warning_or_error(line):
         return line.startswith('CONSOLE ERROR:') or line.startswith('CONSOLE WARNING:')
 
     lines = content_text.strip().splitlines()
     return any(is_warning_or_error(line) for line in lines)