Adding telemetry test for page scroll using scrollbar drag.

This CL adds a telemetry benchmark to use gmail page and uses the
scrollbar and mouss drag action to scroll the page. The test calculates
the mid-point of scrollbar and drags it till the end of the page.

BUG=464685

Review URL: https://codereview.chromium.org/985603003

Cr-Commit-Position: refs/heads/master@{#319629}

tools/perf/page_sets/top_25_smooth.py

@@ -53,6 +53,51 @@ class GmailSmoothPage(top_pages.GmailPage):
     interaction.End()
 
 
+class GmailMouseScrollPage(top_pages.GmailPage):
+
+  """ Why: productivity, top google properties """
+
+  def RunPageInteractions(self, action_runner):
+    action_runner.ExecuteJavaScript('''
+        gmonkey.load('2.0', function(api) {
+          window.__scrollableElementForTelemetry = api.getScrollableElement();
+        });''')
+    action_runner.WaitForJavaScriptCondition(
+        'window.__scrollableElementForTelemetry != null')
+    scrollbar_x, start_y, end_y = self._CalculateScrollBarRatios(action_runner)
+
+    interaction = action_runner.BeginGestureInteraction(
+        'DragAction', is_smooth=True)
+    action_runner.DragPage(left_start_ratio=scrollbar_x,
+        top_start_ratio=start_y, left_end_ratio=scrollbar_x,
+        top_end_ratio=end_y, speed_in_pixels_per_second=100,
+        element_function='window.__scrollableElementForTelemetry')
+    interaction.End()
+
+  def CanRunOnBrowser(self, browser_info):
+    return (browser_info._browser._platform_backend.platform.GetOSName() !=
+        'android')
+
+  def _CalculateScrollBarRatios(self, action_runner):
+    viewport_height = float(action_runner.EvaluateJavaScript(
+        'window.__scrollableElementForTelemetry.clientHeight'))
+    content_height = float(action_runner.EvaluateJavaScript(
+        'window.__scrollableElementForTelemetry.scrollHeight'))
+    viewport_width = float(action_runner.EvaluateJavaScript(
+        'window.__scrollableElementForTelemetry.offsetWidth'))
+    scrollbar_width = float(action_runner.EvaluateJavaScript('''
+        window.__scrollableElementForTelemetry.offsetWidth -
+        window.__scrollableElementForTelemetry.scrollWidth'''))
+
+    # This calculation is correct only when the element doesn't have border or
+    # padding or scroll buttons (eg: gmail mail element).
+    scrollbar_start_mid_y = viewport_height / (2 * content_height)
+    scrollbar_end_mid_y = 1 - scrollbar_start_mid_y
+    scrollbar_mid_x_offset = scrollbar_width / (2 * viewport_width)
+    scrollbar_mid_x = 1 - scrollbar_mid_x_offset
+    return scrollbar_mid_x, scrollbar_start_mid_y, scrollbar_end_mid_y
+
+
 class GoogleCalendarSmoothPage(top_pages.GoogleCalendarPage):
 
   """ Why: productivity, top google properties """
@@ -118,6 +163,7 @@ class Top25SmoothPageSet(page_set_module.PageSet):
     self.AddUserStory(_CreatePageClassWithSmoothInteractions(
         top_pages.GoogleWebSearchPage)(self))
     self.AddUserStory(GmailSmoothPage(self))
+    self.AddUserStory(GmailMouseScrollPage(self))
     self.AddUserStory(GoogleCalendarSmoothPage(self))
     self.AddUserStory(_CreatePageClassWithSmoothInteractions(
         top_pages.GoogleImageSearchPage)(self))

tools/telemetry/telemetry/page/actions/action_runner.py

@@ -241,7 +241,8 @@ class ActionRunner(object):
         selector=selector, text=text, element_function=element_function))
 
   def DragPage(self, left_start_ratio, top_start_ratio, left_end_ratio,
-               top_end_ratio, speed_in_pixels_per_second=800, use_touch=False):
+               top_end_ratio, speed_in_pixels_per_second=800, use_touch=False,
+               selector=None, text=None, element_function=None):
     """Perform a drag gesture on the page.
 
     You should specify a start and an end point in ratios of page width and
@@ -267,7 +268,8 @@ class ActionRunner(object):
         left_start_ratio=left_start_ratio, top_start_ratio=top_start_ratio,
         left_end_ratio=left_end_ratio, top_end_ratio=top_end_ratio,
         speed_in_pixels_per_second=speed_in_pixels_per_second,
-        use_touch=use_touch))
+        use_touch=use_touch, selector=selector, text=text,
+        element_function=element_function))
 
   def PinchPage(self, left_anchor_ratio=0.5, top_anchor_ratio=0.5,
                 scale_factor=None, speed_in_pixels_per_second=800):