Introduce UserStory & UserStorySet classes.

tools/telemetry/telemetry/page/page_set.py

Index: tools/telemetry/telemetry/page/page_set.py
diff --git a/tools/telemetry/telemetry/page/page_set.py b/tools/telemetry/telemetry/page/page_set.py
index 337553244dbb7557c38b5e07bc2236a2d20477f5..a3b40acd5de1292fd3808398d9e23a9bccb850f6 100644
--- a/tools/telemetry/telemetry/page/page_set.py
+++ b/tools/telemetry/telemetry/page/page_set.py
@@ -8,6 +8,7 @@ import os
 
 from telemetry.page import page as page_module
 from telemetry.page import page_set_archive_info
+from telemetry.user_story import user_story_set
 from telemetry.util import cloud_storage
 
 PUBLIC_BUCKET = cloud_storage.PUBLIC_BUCKET
@@ -19,11 +20,12 @@ class PageSetError(Exception):
   pass
 
 
-class PageSet(object):
+class PageSet(user_story_set.UserStorySet):
   def __init__(self, file_path=None, archive_data_file='',
                credentials_path=None, user_agent_type=None,
                make_javascript_deterministic=True, startup_url='',
                serving_dirs=None, bucket=None):
+    super(PageSet, self).__init__()
     # The default value of file_path is location of the file that define this
     # page set instance's class.
     if file_path is None:
@@ -40,7 +42,7 @@ class PageSet(object):
     self.make_javascript_deterministic = make_javascript_deterministic
     self._wpr_archive_info = None
     self.startup_url = startup_url
-    self.pages = []
+    self.user_stories = []
     self.serving_dirs = set()
     serving_dirs = [] if serving_dirs is None else serving_dirs
     # Makes sure that page_set's serving_dirs are absolute paths
@@ -54,26 +56,23 @@ class PageSet(object):
     else:
       raise ValueError("Pageset privacy bucket %s is invalid" % bucket)
 
-  @classmethod
-  def Name(cls):
-    return cls.__module__.split('.')[-1]
+  @property
+  def pages(self):
+    return self.user_stories
 
-  @classmethod
-  def Description(cls):
-    if cls.__doc__:
-      return cls.__doc__.splitlines()[0]
-    else:
-      return ''
+  def AddUserStory(self, user_story):
+    assert isinstance(user_story, page_module.Page)
+    assert user_story.page_set is self
+    super(PageSet, self).AddUserStory(user_story)
 
   def AddPage(self, page):
-    assert page.page_set is self
-    self.pages.append(page)
+    self.AddUserStory(page)
 
   def AddPageWithDefaultRunNavigate(self, page_url):
     """ Add a simple page with url equals to page_url that contains only default
     RunNavigateSteps.
     """
-    self.AddPage(page_module.Page(
+    self.AddUserStory(page_module.Page(
       page_url, self, self.base_dir))
 
   @staticmethod
@@ -109,7 +108,7 @@ class PageSet(object):
     self._wpr_archive_info = value
 
   def ContainsOnlyFileURLs(self):
-    for page in self.pages:
+    for page in self.user_stories:
       if not page.is_file:
         return False
     return True
@@ -117,10 +116,10 @@ class PageSet(object):
   def ReorderPageSet(self, results_file):
     """Reorders this page set based on the results of a past run."""
     page_set_dict = {}
-    for page in self.pages:
+    for page in self.user_stories:
       page_set_dict[page.url] = page
 
-    pages = []
+    user_stories = []
     with open(results_file, 'rb') as csv_file:
       csv_reader = csv.reader(csv_file)
       csv_header = csv_reader.next()
@@ -136,21 +135,9 @@ class PageSet(object):
         else:
           raise Exception('Unusable results_file.')
 
-    return pages
+    return user_stories
 
   def WprFilePathForPage(self, page):
     if not self.wpr_archive_info:
       return None
     return self.wpr_archive_info.WprFilePathForPage(page)
-
-  def __iter__(self):
-    return self.pages.__iter__()
-
-  def __len__(self):
-    return len(self.pages)
-
-  def __getitem__(self, key):
-    return self.pages[key]
-
-  def __setitem__(self, key, value):
-    self.pages[key] = value