rebaseline_server: use new intermediate JSON format

gm/rebaseline_server/imagepair_test.py

 #!/usr/bin/python
 
 """
 Copyright 2014 Google Inc.
 
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 
 Test imagepair.py
 """
@@ skipping 69 matching lines @@
             'arcofzorro/16206093933823793653.png',
             'arcofzorro/13786535001616823825.png',
             None,
             None,
             # expected output:
             {
                 'differenceData': {
                     'maxDiffPerChannel': [255, 255, 247],
                     'numDifferingPixels': 662,
                     'percentDifferingPixels': 0.0662,
+                    'perceptualDifference': 0.06620000000000914,
                     'weightedDiffMeasure': 0.01127756555171088,
                 },
                 'imageAUrl': 'arcofzorro/16206093933823793653.png',
                 'imageBUrl': 'arcofzorro/13786535001616823825.png',
                 'isDifferent': True,
             },
         ],
 
         [
             # inputs:
             'gradients_degenerate_2pt/10552995703607727960.png',
             'gradients_degenerate_2pt/11198253335583713230.png',
             {
                 'ignoreFailure': True,
                 'bugs': [1001, 1002],
             },
             {
                 'builder': 'MyBuilder',
                 'test': 'MyTest',
             },
             # expected output:
             {
                 'differenceData': {
                     'maxDiffPerChannel': [255, 0, 255],
                     'numDifferingPixels': 102400,
                     'percentDifferingPixels': 100.00,
+                    'perceptualDifference': 100.00,
                     'weightedDiffMeasure': 66.66666666666667,
                 },
                 'expectations': {
                     'bugs': [1001, 1002],
                     'ignoreFailure': True,
                 },
                 'extraColumns': {
                     'builder': 'MyBuilder',
                     'test': 'MyTest',
                 },
@@ skipping 18 matching lines @@
       self.assertEqual(image_pair.as_dict(), selftest[4])
 
 
 def main():
   suite = unittest.TestLoader().loadTestsFromTestCase(ImagePairTest)
   unittest.TextTestRunner(verbosity=2).run(suite)
 
 
 if __name__ == '__main__':
   main()