Synthetic pinch gesture take scale factor as parameter.

tools/perf/page_sets/tough_pinch_zoom_cases.py

Index: tools/perf/page_sets/tough_pinch_zoom_cases.py
diff --git a/tools/perf/page_sets/tough_pinch_zoom_cases.py b/tools/perf/page_sets/tough_pinch_zoom_cases.py
index 799cfc4547ef9e33496f0560c6d008c2adc6d432..a65f4ea4cd1448e3f1ee0e4a11dcce409119907a 100644
--- a/tools/perf/page_sets/tough_pinch_zoom_cases.py
+++ b/tools/perf/page_sets/tough_pinch_zoom_cases.py
@@ -78,7 +78,7 @@ class GoogleCalendarPage(ToughPinchZoomCasesPage):
     action_runner.RunAction(PinchAction(
       {
         'left_anchor_percentage': 0.1,
-        'top_anchor_percentage': 0.1
+        'top_anchor_percentage': 0.3
       }))
 
 
@@ -118,7 +118,7 @@ class GooglePlusPage(ToughPinchZoomCasesPage):
       {
         'element_function': '''
           function(callback) {
-            callback(document.getElementsByClassName("Ct")[0])
+            callback(document.getElementById("110031535020051778989-tab-bar"))
           }'''
       }))
 
@@ -245,6 +245,26 @@ class YahooGamePage(ToughPinchZoomCasesPage):
     action_runner.RunAction(NavigateAction())
     action_runner.RunAction(WaitAction({'seconds':2}))
 
+
+class YahooAnswersPage(ToughPinchZoomCasesPage):
+
+  """ Why: #1 Alexa reference """
+
+  def __init__(self, page_set):
+    super(YahooAnswersPage, self).__init__(
+      url='http://answers.yahoo.com',
+      page_set=page_set)
+
+  def RunSmoothness(self, action_runner):
+    action_runner.RunAction(PinchAction(
+      {
+        'element_function': '''
+          function(callback) {
+            callback(document.getElementById("ya-content-apps"))
+          }'''
+      }))
+
+
 class ToughPinchZoomCasesPageSet(page_set_module.PageSet):
 
   """ Set of pages that are tricky to pinch-zoom """
@@ -288,8 +308,7 @@ class ToughPinchZoomCasesPageSet(page_set_module.PageSet):
     # Why: #1 Alexa recreation
     self.AddPage(ToughPinchZoomCasesPage('http://booking.com', self))
 
-    # Why: #1 Alexa reference
-    self.AddPage(ToughPinchZoomCasesPage('http://answers.yahoo.com', self))
+    self.AddPage(YahooAnswersPage(self))
 
     # Why: #1 Alexa sports
     self.AddPage(ToughPinchZoomCasesPage('http://sports.yahoo.com/', self))