[I-Spy] Add support for rebaselining expectations from the web UI.

chrome/test/functional/ispy/server/main_view_handler.py

 # Copyright 2013 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.
 
 """Request handler to serve the main_view page."""
 
 import jinja2
 import json
 import os
 import re
 import sys
 import webapp2
 
-from ..common import constants
-from ..common import ispy_utils
+from common import chrome_utils
+from common import constants
+from common import ispy_utils
 
 import gs_bucket
 import views
 
 JINJA = jinja2.Environment(
     loader=jinja2.FileSystemLoader(os.path.dirname(views.__file__)),
     extensions=['jinja2.ext.autoescape'])
 
 
 class MainViewHandler(webapp2.RequestHandler):
@@ skipping 34 matching lines @@
 
     This method will produce a list of failure-rows that are sorted
     in descending order by number of different pixels.
 
     Args:
       test_run: The name of the test_run to render failure rows from.
       ispy: An instance of ispy_utils.ISpyUtils.
     """
     paths = set([path for path in ispy.GetAllPaths('failures/' + test_run)
                  if path.endswith('actual.png')])
+    can_rebaseline = chrome_utils.ChromeUtils(
+        ispy.cloud_bucket).CanRebaselineToTestRun(test_run)
     rows = [self._CreateRow(test_run, path, ispy) for path in paths]
-    if rows:
-      # Function that sorts by the different_pixels field in the failure-info.
-      def _Sorter(a, b):
-        return cmp(b['percent_different'],
-                   a['percent_different'])
-      template = JINJA.get_template('main_view.html')
-      self.response.write(
-          template.render({'comparisons': sorted(rows, _Sorter),
-                           'test_run': test_run}))
-    else:
-      template = JINJA.get_template('empty_view.html')
-      self.response.write(template.render())
+
+    # Function that sorts by the different_pixels field in the failure-info.
+    def _Sorter(a, b):
+      return cmp(b['percent_different'],
+                 a['percent_different'])
+    template = JINJA.get_template('main_view.html')
+    self.response.write(
+        template.render({'comparisons': sorted(rows, _Sorter),
+                         'test_run': test_run,
+                         'can_rebaseline': can_rebaseline}))
 
   def _CreateRow(self, test_run, path, ispy):
     """Creates one failure-row.
 
     This method builds a dictionary with the data necessary to display a
     failure in the main_view html template.
 
     Args:
       test_run: The name of the test_run the failure is in.
       path: A path to the failure's actual.png file.
@@ skipping 13 matching lines @@
         res['expectation'], 'expected.png')
     diff = ispy_utils.GetFailurePath(test_run, res['expectation'], 'diff.png')
     res['percent_different'] = res['info']['fraction_different'] * 100
     res['expected_path'] = expected
     res['diff_path'] = diff
     res['actual_path'] = path
     res['expected'] = ispy.cloud_bucket.GetImageURL(expected)
     res['diff'] = ispy.cloud_bucket.GetImageURL(diff)
     res['actual'] = ispy.cloud_bucket.GetImageURL(path)
     return res