Fix record_wpr to allow page tests to customize browser options.

tools/telemetry/telemetry/page/record_wpr_unittest.py

Index: tools/telemetry/telemetry/page/record_wpr_unittest.py
diff --git a/tools/telemetry/telemetry/page/record_wpr_unittest.py b/tools/telemetry/telemetry/page/record_wpr_unittest.py
index 9642d5a104c8a9f9a51880f0ff71a981fc945290..9bfef35bb8be1e68d3aa9be75d93d3e6455c3dcf 100644
--- a/tools/telemetry/telemetry/page/record_wpr_unittest.py
+++ b/tools/telemetry/telemetry/page/record_wpr_unittest.py
@@ -46,6 +46,9 @@ class MockPageTest(page_test.PageTest):
     self._action_name_to_run = "RunPageInteractions"
     self.func_calls = []
 
+  def CustomizeBrowserOptions(self, options):
+    self.func_calls.append('CustomizeBrowserOptions')
+
   def WillNavigateToPage(self, page, tab):
     self.func_calls.append('WillNavigateToPage')
 
@@ -189,12 +192,18 @@ class RecordWprUnitTests(tab_test_case.TabTestCase):
     self.assertEqual(wpr_modes.WPR_RECORD,
                      wpr_recorder.options.browser_options.wpr_mode)
 
-  # When the RecorderPageTest WillStartBrowser/DidStartBrowser function is
-  # called, it forwards the call to the PageTest
+  # When the RecorderPageTest CustomizeBrowserOptions/WillStartBrowser/
+  # DidStartBrowser function is called, it forwards the call to the PageTest
   def testRecorderPageTest_BrowserMethods(self):
+    flags = ['--mock-benchmark-url', self._url]
     record_page_test = record_wpr.RecorderPageTest()
     record_page_test.page_test = MockBenchmark().test()
+    wpr_recorder = record_wpr.WprRecorder(self._test_data_dir, MockBenchmark(),
+                                          flags)
+    record_page_test.CustomizeBrowserOptions(wpr_recorder.options)
     record_page_test.WillStartBrowser(self._tab.browser.platform)
     record_page_test.DidStartBrowser(self._tab.browser)
+    self.assertTrue(
+        'CustomizeBrowserOptions' in record_page_test.page_test.func_calls)
     self.assertTrue('WillStartBrowser' in record_page_test.page_test.func_calls)
     self.assertTrue('DidStartBrowser' in record_page_test.page_test.func_calls)