Adding support for diagonal scrolling to telemetry.

tools/telemetry/telemetry/page/actions/scroll_unittest.py

 # Copyright 2012 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 os
 
 from telemetry import decorators
 from telemetry.page.actions import scroll
 from telemetry.unittest_util import tab_test_case
 
 
 class ScrollActionTest(tab_test_case.TabTestCase):
-  @decorators.Disabled  # Disabled due to flakiness: crbug.com/330544

[nednguyen, 2015/03/04 05:40:49]

Can you make a separate patch for enabling this? The less moving pieces in a
patch, the easier it's to keep track & revert if things go wrong.

   def testScrollAction(self):
     self.Navigate('blank.html')
 
     # Make page bigger than window so it's scrollable.
     self._tab.ExecuteJavaScript("""document.body.style.height =
                               (2 * window.innerHeight + 1) + 'px';""")
 
     self.assertEquals(
         self._tab.EvaluateJavaScript("""document.documentElement.scrollTop
                                    || document.body.scrollTop"""), 0)
@@ skipping 16 matching lines @@
     # Allow for roundoff error in scaled viewport.
     scroll_position = self._tab.EvaluateJavaScript(
         """(document.documentElement.scrollTop || document.body.scrollTop)
         + window.innerHeight""")
     scroll_height = self._tab.EvaluateJavaScript('document.body.scrollHeight')
     difference = scroll_position - scroll_height
     self.assertTrue(abs(difference) <= 1,
                     msg='scroll_position=%d; scroll_height=%d' %
                             (scroll_position, scroll_height))
 
+  def testDiagonalScrollAction(self):
+    self.Navigate('blank.html')
+
+    # Make page bigger than window so it's scrollable.
+    self._tab.ExecuteJavaScript("""document.body.style.height =
+                              (2 * window.innerHeight + 1) + 'px';""")
+    self._tab.ExecuteJavaScript("""document.body.style.width =
+                              (2 * window.innerWidth + 1) + 'px';""")
+
+    self.assertEquals(
+        self._tab.EvaluateJavaScript("""document.documentElement.scrollTop
+                                   || document.body.scrollTop"""), 0)
+    self.assertEquals(
+        self._tab.EvaluateJavaScript("""document.documentElement.scrollLeft
+                                   || document.body.scrollLeft"""), 0)
+
+    i = scroll.ScrollAction(direction='downright')
+    i.WillRunAction(self._tab)
+
+    self._tab.ExecuteJavaScript("""
+        window.__scrollAction.beginMeasuringHook = function() {
+            window.__didBeginMeasuring = true;
+        };
+        window.__scrollAction.endMeasuringHook = function() {
+            window.__didEndMeasuring = true;
+        };""")
+    i.RunAction(self._tab)
+
+    self.assertTrue(self._tab.EvaluateJavaScript('window.__didBeginMeasuring'))
+    self.assertTrue(self._tab.EvaluateJavaScript('window.__didEndMeasuring'))
+
+    # Allow for roundoff error in scaled viewport.
+    viewport_bottom = self._tab.EvaluateJavaScript(
+        """(document.documentElement.scrollTop || document.body.scrollTop)
+        + window.innerHeight""")
+    page_height = self._tab.EvaluateJavaScript('document.body.scrollHeight')
+    viewport_right = self._tab.EvaluateJavaScript(
+        """(document.documentElement.scrollLeft || document.body.scrollLeft)
+        + window.innerWidth""")
+    page_width = self._tab.EvaluateJavaScript('document.body.scrollWidth')
+
+    # The diagonal scrolling behaves like a square.
+    # It will not continue scrolling down if it cannot also scroll right.
+    # So determine which axis scrolled all the way to its end.
+    vertical_difference = abs(viewport_bottom - page_height)
+    horizontal_difference = abs(viewport_right - page_width)
+    scroll_distance = min(vertical_difference, horizontal_difference)
+    self.assertTrue(scroll_distance <= 1,
+                    msg=('vertical_difference=%d; '
+                         'horizontal_difference=%d; '
+                         'scroll_distance=%d '
+                         'page_height=%d '
+                         'page_width=%d') %
+                            (vertical_difference,
+                             horizontal_difference,
+                             scroll_distance,
+                             page_height,
+                             page_width))
+
   def testBoundingClientRect(self):
     self.Navigate('blank.html')
 
     with open(os.path.join(os.path.dirname(__file__),
                            'gesture_common.js')) as f:
       js = f.read()
       self._tab.ExecuteJavaScript(js)
 
     # Verify that the rect returned by getBoundingVisibleRect() in scroll.js is
     # completely contained within the viewport. Scroll events dispatched by the
@@ skipping 26 matching lines @@
     viewport_width = int(self._tab.EvaluateJavaScript('window.innerWidth'))
 
     self.assertTrue(rect_top >= 0,
         msg='%s >= %s' % (rect_top, 0))
     self.assertTrue(rect_left >= 0,
         msg='%s >= %s' % (rect_left, 0))
     self.assertTrue(rect_bottom <= viewport_height,
         msg='%s + %s <= %s' % (rect_top, rect_height, viewport_height))
     self.assertTrue(rect_right <= viewport_width,
         msg='%s + %s <= %s' % (rect_left, rect_width, viewport_width))