[chrome_remote_control] Add pylint to PRESUMMIT and fix lint

tools/chrome_remote_control/chrome_remote_control/page_set.py

 # Copyright (c) 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 json
 import urlparse
 
 class Page(object):
-  def __init__(self, url, attributes={}):
+  def __init__(self, url, attributes=None):
     self.url = url
     parsed_url = urlparse.urlparse(url)
-    if parsed_url.scheme == None:
+    if parsed_url.scheme == None: # pylint: disable=E1101
       raise Exception('urls must be fully qualified: %s' % url)
     self.interactions = 'scroll'
     self.credentials = None
     self.wait_time_after_navigate = 2
     self.scroll_is_infinite = False
 
-    for k, v in attributes.iteritems():
-      setattr(self, k, v)
+    if attributes:
+      for k, v in attributes.iteritems():
+        setattr(self, k, v)
 
   def __str__(self):
     return self.url
 
 class PageSet(object):
   def __init__(self, description='', file_path=''):
     self.description = description
     self.file_path = file_path
     self.pages = []
 
   @classmethod
   def FromFile(cls, file_path):
     with open(file_path, 'r') as f:
       contents = f.read()
       data = json.loads(contents)
       return cls.FromDict(data, file_path)
 
   @classmethod
   def FromDict(cls, data, file_path=''):
     page_set = cls(data['description'], file_path)
     for page_attributes in data['pages']:
       url = page_attributes.pop('url')
       page = Page(url, page_attributes)
       page_set.pages.append(page)
     return page_set
 
   def __iter__(self):
     return self.pages.__iter__()