Add fuzzy image matching tool for Linux pixel tests

webkit/tools/layout_tests/layout_package/test_failures.py

 # Copyright (c) 2006-2008 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.
 
 """Classes for failures that occur during tests."""
 
 import path_utils
 
 class FailureSort(object):
   """A repository for failure sort orders and tool to facilitate sorting."""
@@ skipping 184 matching lines @@
 class FailureImageHashMismatch(FailureWithType):
   """Image hashes didn't match."""
   OUT_FILENAMES = ["-actual-win.png", "-expected.png"]
 
   @staticmethod
   def Message():
     # We call this a simple image mismatch to avoid confusion, since we link
     # to the PNGs rather than the checksums.
     return "Image mismatch"
 
+class FailureFuzzyFailure(FailureWithType):
+  """Image hashes didn't match."""
+  OUT_FILENAMES = ["-actual-win.png", "-expected.png"]
+
+  @staticmethod
+  def Message():
+    return "Fuzzy image match also failed"