Add Wait* API to ActionRunner to wrap over WaitAction.

tools/perf/page_sets/gmail_compose_discard.py

Index: tools/perf/page_sets/gmail_compose_discard.py
diff --git a/tools/perf/page_sets/gmail_compose_discard.py b/tools/perf/page_sets/gmail_compose_discard.py
index 264878ba90b73baaca375f336e19b9f0bf8d7a3b..018dd9eec9968b4e989a574b3d14fe7a3aeaff2e 100644
--- a/tools/perf/page_sets/gmail_compose_discard.py
+++ b/tools/perf/page_sets/gmail_compose_discard.py
@@ -1,12 +1,21 @@
 # Copyright 2014 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 re
+
 # pylint: disable=W0401,W0614
 from telemetry.page.actions.all_page_actions import *
 from telemetry.page import page as page_module
 from telemetry.page import page_set as page_set_module
 
 
+def _CreateXpathFunction(xpath):
+  return ('document.evaluate(%s, document, null, '
+          'XPathResult.FIRST_ORDERED_NODE_TYPE, null)'
+          '.singleNodeEvaluate') % re.escape(xpath)
+
+
 class GmailComposeDiscardPage(page_module.Page):
 
   """ Why: Compose and discard a new email """
@@ -21,12 +30,9 @@ class GmailComposeDiscardPage(page_module.Page):
 
   def RunNavigateSteps(self, action_runner):
     action_runner.NavigateToPage(self)
-    action_runner.RunAction(WaitAction(
-      {
-        'javascript': (
-          'window.gmonkey !== undefined &&'
-          'document.getElementById("gb") !== null')
-      }))
+    action_runner.WaitForJavaScriptCondition(
+        'window.gmonkey !== undefined &&'
+        'document.getElementById("gb") !== null')
 
   def ComposeClick(self, action_runner):
     action_runner.ExecuteJavaScript('''
@@ -41,23 +47,17 @@ class GmailComposeDiscardPage(page_module.Page):
       button.dispatchEvent(mouseupevent);''')
 
   def RunEndure(self, action_runner):
-    action_runner.RunAction(WaitAction(
-      {
-        'xpath': '//div[text()="COMPOSE"]',
-        'condition': 'element'
-      }))
+    action_runner.WaitForElement(
+        element_function=_CreateXpathFunction('//div[text()="COMPOSE"]'))
     self.ComposeClick(action_runner)
-    action_runner.RunAction(WaitAction({"seconds": 1}))
-    action_runner.RunAction(WaitAction(
-      {
-        'condition': 'element',
-        'selector': 'div[class~="oh"][data-tooltip="Discard draft"]'
-      }))
+    action_runner.Wait(1)
+    action_runner.WaitForElement(
+        'div[class~="oh"][data-tooltip="Discard draft"]')
     action_runner.RunAction(ClickElementAction(
       {
         'selector': 'div[class~="oh"][data-tooltip="Discard draft"]'
       }))
-    action_runner.RunAction(WaitAction({'seconds': 1}))
+    action_runner.Wait(1)
 
 
 class GmailComposeDiscardPageSet(page_set_module.PageSet):