Add Web Animations performance tests

tools/perf/page_sets/tough_animation_cases.py

Index: tools/perf/page_sets/tough_animation_cases.py
diff --git a/tools/perf/page_sets/tough_animation_cases.py b/tools/perf/page_sets/tough_animation_cases.py
index ae0b8ec16ff352fced3e5f6bc205a374876a37a7..86ac0e8cb7293da47b2504e51a23b3778eb3a261 100644
--- a/tools/perf/page_sets/tough_animation_cases.py
+++ b/tools/perf/page_sets/tough_animation_cases.py
@@ -103,6 +103,27 @@ class ToughAnimationCasesPageSet(page_set_module.PageSet):
       # updating inline style.
       # pylint: disable=C0301
       'file://tough_animation_cases/css_transitions_staggered_triggering_by_updating_inline_style.html?N=0316',
+
+      # Why: Tests many Web Animations all starting at the same time with 500
+      # keyframes each.
+      'file://tough_animation_cases/web_animations_many_keyframes.html?N=0316',
+      # Why: Tests many paused Web Animations having their currentTimes updated
+      # in every requestAnimationFrame.
+      # pylint: disable=C0301
+      'file://tough_animation_cases/web_animations_set_current_time_in_raf.html?N=0316',
+      # Why: Tests many Web Animations all starting at the same time.
+      'file://tough_animation_cases/web_animations_simultaneous.html?N=0316',
+      # Why: Tests many Web Animations all starting at different times then
+      # chained together using events.
+      # pylint: disable=C0301
+      'file://tough_animation_cases/web_animations_staggered_chaining.html?N=0316',
+      # Why: Tests many Web Animations all starting at different times with
+      # infinite iterations.
+      # pylint: disable=C0301
+      'file://tough_animation_cases/web_animations_staggered_infinite_iterations.html?N=0316',
+      # Why: Tests many Web Animations all starting at different times.
+      # pylint: disable=C0301
+      'file://tough_animation_cases/web_animations_staggered_triggering.html?N=0316',
     ]
 
     for url in urls_list_one: