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

chrome/test/functional/ispy/server/rebaseline_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 that updates the Expectation version."""
+
+import webapp2
+
+from common import constants
+from common import chrome_utils
+
+import gs_bucket
+
+
+class RebaselineHandler(webapp2.RequestHandler):
+  """Request handler to allow test mask updates."""
+
+  def post(self):
+    """Accepts post requests.
+
+    Expects a test_run as a parameter and updates the associated version file to
+    use the expectations associated with that test run.
+    """
+    test_run = self.request.get('test_run')
+
+    # Fail if test_run parameter is missing.
+    if not test_run:
+      self.response.header['Content-Type'] = 'json/application'
+      self.response.write(json.dumps(
+          {'error': '\'test_run\' must be supplied to rebaseline.'}))
+      return
+    # Otherwise, set up the utilities.
+    bucket = gs_bucket.GoogleCloudStorageBucket(constants.BUCKET)
+    chrome_util = chrome_utils.ChromeUtils(bucket)
+    # Fail if the test run is not associated with a set of Expectations.
+    if not chrome_util.CanRebaselineToTestRun(test_run):
+      self.response.header['Content-Type'] = 'json/application'
+      self.response.write(json.dumps(
+        {'error': 'Can not rebaseline to the given test run.'}))
+      return
+    # Update versions file.
+    chrome_util.RebaselineToTestRun(test_run)
+    # Redirect back to the sites list for the test run.
+    self.redirect('/?test_run=%s' % test_run)