Adding tests for diagonal scrolling in telemetry.

tools/perf/page_sets/tough_scrolling_while_zoomed_in_cases.py

+# Copyright 2015 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.
+from page_sets import diagonal_scrolling_supported_shared_state
+
+from telemetry.page import shared_page_state
+from telemetry.page import page as page_module
+from telemetry.page import page_set as page_set_module
+from telemetry.core.backends.chrome_inspector import devtools_client_backend
+
+
+class ToughScrollingWhileZoomedInCasesPage(page_module.Page):
+
+  def __init__(self, url, page_set):
+    super(ToughScrollingWhileZoomedInCasesPage, self).__init__(
+        url=url,
+        page_set=page_set,
+        shared_page_state_class=(
+            diagonal_scrolling_supported_shared_state.
+            DiagonalScrollingSupportedSharedState))
+
+  def RunPageInteractions(self, action_runner):
+    # First, zoom into the page
+    action_runner.PinchPage(
+        scale_factor=20.0,
+        speed_in_pixels_per_second=10000)
+        # 20.0 was chosen because at the time it was close to the maximum.

[nednguyen, 2015/04/06 21:31:25]

Nits: can you indent these lines to the left?

+        # The more zoomed in, the more noticable the tile rasterization.
+        #
+        # 10,000 was chosen to complete this pre-step quickly.
+
+    # Then start measurements
+    interaction = action_runner.BeginGestureInteraction('ScrollAction')
+    # And begin the diagonal scroll
+    action_runner.ScrollPage(
+        direction='downright',
+        speed_in_pixels_per_second=10000)
+          # 10,000 was chosen because it is fast enough to completely stress the
+          # rasterization (on a Nexus 5) without saturating results.
+    interaction.End()
+
+
+class ToughScrollingWhileZoomedInCasesPageSet(page_set_module.PageSet):
+  """
+  Description: A collection of difficult scrolling tests
+  """
+
+  def __init__(self):
+    super(ToughScrollingWhileZoomedInCasesPageSet, self).__init__(
+        user_agent_type='desktop',
+        archive_data_file='data/tough_pinch_zoom_cases.json',
+        bucket=page_set_module.PARTNER_BUCKET)
+
+    # The following urls were chosen because they tend to have >15%
+    # mean_pixels_approximated at this scrolling speed.
+    urls_list = [
+        'file://tough_scrolling_cases/background_fixed.html',
+        'file://tough_scrolling_cases/fixed_nonstacking.html',
+        'file://tough_scrolling_cases/iframe_scrolls.html',
+        'file://tough_scrolling_cases/wheel_div_prevdefault.html'
+    ]
+
+    for url in urls_list:
+      self.AddUserStory(ToughScrollingWhileZoomedInCasesPage(url, self))