Add {Will,Did}StartBrowser to record_wpr

tools/telemetry/telemetry/page/record_wpr.py

Index: tools/telemetry/telemetry/page/record_wpr.py
diff --git a/tools/telemetry/telemetry/page/record_wpr.py b/tools/telemetry/telemetry/page/record_wpr.py
index c88df05518f3f5f2dced40aba8d93f29a0c5312f..dc3da9305f5c1706bb8238814773029e787bd43b 100755
--- a/tools/telemetry/telemetry/page/record_wpr.py
+++ b/tools/telemetry/telemetry/page/record_wpr.py
@@ -39,6 +39,14 @@ class RecorderPageTest(page_test.PageTest):  # pylint: disable=W0223
     if self.page_test:
       self.page_test.DidNavigateToPage(page, tab)
 
+  def WillStartBrowser(self, browser):
+    if self.page_test:
+      self.page_test.WillStartBrowser(browser)
+
+  def DidStartBrowser(self, browser):
+    if self.page_test:
+      self.page_test.DidStartBrowser(browser)
+
   def WillRunActions(self, page, tab):
     if self.page_test:
       self.page_test.WillRunActions(page, tab)
@@ -133,6 +141,10 @@ class WprRecorder(object):
   def options(self):
     return self._options
 
+  @property
+  def page_test(self):
+    return self._record_page_test.page_test if self._benchmark else None
+
   def _CreateOptions(self):
     options = browser_options.BrowserFinderOptions()
     options.browser_options.wpr_mode = wpr_modes.WPR_RECORD