Upgrade loading_model to use the new request_track and loading_trace.

tools/android/loading/request_track.py

 # Copyright (c) 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.
 
 """The request data track.
 
 When executed, parses a JSON dump of DevTools messages.
 """
 
 import collections
@@ skipping 99 matching lines @@
     """Returns the content type, or None."""
     content_type = self.response_headers.get('Content-Type', None)
     if not content_type or ';' not in content_type:
       return content_type
     else:
       return content_type[:content_type.index(';')]
 
   def IsDataRequest(self):
     return self.protocol == 'data'
 
-  # For testing.
+  def MaxAge(self):
+    """Returns the max-age of a resource, or -1."""
+    # TODO(lizeb): Handle the "Expires" header as well.
+    cache_control = {}
+    if not self.response_headers:
+      return -1
+    cache_control_str = self.response_headers.get('Cache-Control', None)
+    if cache_control_str is not None:
+      directives = [s.strip() for s in cache_control_str.split(',')]
+      for directive in directives:
+        parts = [s.strip() for s in directive.split('=')]
+        if len(parts) == 1:
+          cache_control[parts[0]] = True
+        else:
+          cache_control[parts[0]] = parts[1]
+    if (u'no-store' in cache_control
+        or u'no-cache' in cache_control
+        or len(cache_control) == 0):
+      return -1
+    if 'max-age' in cache_control:
+      return int(cache_control['max-age'])
+    return -1
+
   def __eq__(self, o):
     return self.__dict__ == o.__dict__
 
+  def __hash__(self):
+    return hash(self.request_id)
+
 
 class RequestTrack(devtools_monitor.Track):
   """Aggregates request data."""
   REDIRECT_SUFFIX = '.redirect'
   # Request status
   _STATUS_SENT = 0
   _STATUS_RESPONSE = 1
   _STATUS_DATA = 2
   _STATUS_FINISHED = 3
   _STATUS_FAILED = 4
@@ skipping 171 matching lines @@
 
 
 if __name__ == '__main__':
   import json
   import sys
   events = json.load(open(sys.argv[1], 'r'))
   request_track = RequestTrack(None)
   for event in events:
     event_method = event['method']
     request_track.Handle(event_method, event)