predictors: Take the priority into account for scoring resources.

tools/resource_prefetch_predictor/prefetch_predictor_tool.py

 #!/usr/bin/python
 # 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.
 
 """Inspection of the prefetch predictor database.
 
 On Android, the database can be extracted using:
 adb pull \
   '/data/user/0/$package_name/app_chrome/Default/Network Action Predictor'
@@ skipping 13 matching lines @@
       self, main_page_url, resource_url, proto_buffer):
     self.main_page_url = main_page_url
     self.resource_url = resource_url
     self.proto = ResourceData()
     self.proto.ParseFromString(proto_buffer)
     self.confidence = float(self.proto.number_of_hits / (
         self.proto.number_of_hits + self.proto.number_of_misses))
     self.score = self._Score()
 
   def _Score(self):
-    """Mirrors ResourcePrefetchPredictorTables::ResourceRow::UpdateScore."""
-    multiplier = 1
+    """Mirrors ResourcePrefetchPredictorTables::ComputeResourceScore."""
+    priority_multiplier = 1
+    type_multiplier = 1
+
+    if self.proto.priority == ResourceData.REQUEST_PRIORITY_HIGHEST:
+      priority_multiplier = 3
+    elif self.proto.priority == ResourceData.REQUEST_PRIORITY_MEDIUM:
+      priority_multiplier = 2
+
     if self.proto.resource_type in (ResourceData.RESOURCE_TYPE_STYLESHEET,
-                                    ResourceData.RESOURCE_TYPE_SCRIPT,
-                                    ResourceData.RESOURCE_TYPE_FONT_RESOURCE):
-      multiplier = 2
-    return multiplier * 100 - self.proto.average_position
+                                    ResourceData.RESOURCE_TYPE_SCRIPT):
+      type_multiplier = 3
+    elif self.proto.resource_type == ResourceData.RESOURCE_TYPE_FONT_RESOURCE:
+      type_multiplier = 2
+
+      return (100 * (priority_multiplier * 100 + type_multiplier * 10)
+              - self.proto.average_position)
 
   @classmethod
   def FromRow(cls, row):
     """Builds an entry from a database row."""
     return Entry(*row)
 
   def __str__(self):
     return 'score: %s\nmain_page_url: %s\nconfidence: %f"\n%s' % (
         self.score, self.main_page_url, self.confidence, self.proto)
 
@@ skipping 25 matching lines @@
   parser = argparse.ArgumentParser()
   parser.add_argument('-f', dest='database_filename', required=True,
                       help='Path to the database')
   parser.add_argument('-d', dest='domain', default=None, help='Domain')
   args = parser.parse_args()
   DatabaseStats(args.database_filename, args.domain)
 
 
 if __name__ == '__main__':
   main()