[system_health] Fix the lack of memory dump triggers on some user stories

tools/perf/benchmarks/system_health_unittest.py

 # Copyright 2016 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 sys
 import unittest
 
 from benchmarks import system_health as system_health_benchmark
 from core import path_util
 from page_sets.system_health import system_health_stories
+from page_sets.system_health import system_health_story
 
 from telemetry import benchmark as benchmark_module
 from telemetry.core import discover
 
 
 def _GetAllSystemHealthBenchmarks():
   all_perf_benchmarks = discover.DiscoverClasses(
       path_util.GetPerfBenchmarksDir(), path_util.GetPerfDir(),
       benchmark_module.Benchmark,
       index_by_class_name=True).values()
@@ skipping 16 matching lines @@
           '%r has ShouldTearDownStateAfterEachStoryRun set to False' % b)
 
   def testSystemHealthStorySetIsUsed(self):
     for b in _GetAllSystemHealthBenchmarks():
       if b is system_health_benchmark.WebviewStartupSystemHealthBenchmark:
         continue
       self.assertIsInstance(
           b().CreateStorySet(None),
           system_health_stories.SystemHealthStorySet,
           '%r does not use SystemHealthStorySet' % b)
+
+
+class TestSystemHealthStories(unittest.TestCase):
+
+  def testNoOverrideRunPageInteractions(self):
+    desktop_stories = (
+        system_health_stories.DesktopSystemHealthStorySet().stories)
+    mobile_stories = (
+        system_health_stories.MobileSystemHealthStorySet().stories)
+    for s in desktop_stories + mobile_stories:
+      # Long running stories has their own way of collecting memory dumps,
+      # so they explicitly override RunPageInteractions method.
+      if s.name.startswith('long_running:'):
+        continue
+      self.assertEquals(s.__class__.RunPageInteractions,
+          system_health_story.SystemHealthStory.RunPageInteractions,
+          'Story %s overrides RunPageInteractions. Override _DidLoadDocument '
+          'instead' % s.name)