Support filling in baselines from other platforms in rebaseline-cl.

third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl_unittest.py

 # Copyright 2016 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.
 
 import json
 import optparse
 
 from webkitpy.common.net.buildbot import Build
 from webkitpy.common.net.git_cl import GitCL
 from webkitpy.common.checkout.git_mock import MockGit
@@ skipping 131 matching lines @@
 
     @staticmethod
     def command_options(**kwargs):
         options = {
             'only_changed_tests': False,
             'dry_run': False,
             'optimize': True,
             'results_directory': None,
             'verbose': False,
             'trigger_jobs': False,
+            'fill_missing': False,
         }
         options.update(kwargs)
         return optparse.Values(dict(**options))
 
     def test_execute_basic(self):
         return_code = self.command.execute(self.command_options(), [], self.tool)
         self.assertEqual(return_code, 0)
         self.assertLog([
             'INFO: Rebaselining fast/dom/prototype-inheritance.html\n',
             'INFO: Rebaselining fast/dom/prototype-newtest.html\n',
@@ skipping 170 matching lines @@
 
     def test_bails_when_there_are_unstaged_baselines(self):
         git = self.tool.git()
         git.unstaged_changes = lambda: {'third_party/WebKit/LayoutTests/my-test-expected.txt': '?'}
         return_code = self.command.execute(self.command_options(), [], self.tool)
         self.assertEqual(return_code, 1)
         self.assertLog([
             'ERROR: Aborting: there are unstaged baselines:\n',
             'ERROR:   /mock-checkout/third_party/WebKit/LayoutTests/my-test-expected.txt\n',
         ])
+
+    def test_fill_in_missing_results(self):
+        test_baseline_set = TestBaselineSet(self.tool)
+        test_baseline_set.add('fast/dom/prototype-taco.html', Build('MOCK Try Linux', 100))
+        test_baseline_set.add('fast/dom/prototype-taco.html', Build('MOCK Try Win', 200))
+        self.command.fill_in_missing_results(test_baseline_set)
+        self.assertEqual(
+            test_baseline_set.build_port_pairs('fast/dom/prototype-taco.html'),
+            [
+                (Build(builder_name='MOCK Try Linux', build_number=100), 'test-linux-trusty'),
+                (Build(builder_name='MOCK Try Win', build_number=200), 'test-win-win7'),
+                (Build(builder_name='MOCK Try Linux', build_number=100), 'test-mac-mac10.11'),
+            ])
+        self.assertLog([
+            'INFO: For fast/dom/prototype-taco.html:\n',
+            'INFO: Using Build(builder_name=\'MOCK Try Linux\', build_number=100) to supply results for test-mac-mac10.11.\n',
+        ])