tools: Add a tool to load pages on a device, and pull the predictor database.

tools/android/loading/devtools_monitor.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.
 
 """Library handling DevTools websocket interaction.
 """
 
 import datetime
 import httplib
 import json
@@ skipping 217 matching lines @@
   def MonitorUrl(self, url, timeout_seconds=DEFAULT_TIMEOUT_SECONDS,
                  stop_delay_multiplier=0):
     """Navigate to url and dispatch monitoring loop.
 
     Unless you have registered a listener that will call StopMonitoring, this
     will run until timeout from chrome.
 
     Args:
       url: (str) a URL to navigate to before starting monitoring loop.
       timeout_seconds: timeout in seconds for monitoring loop.
-      stop_delay_multiplier: How long to wait after page load completed before
-        tearing down, relative to the time it took to reach the page load to
-        complete.
+      stop_delay_multiplier: (float) How long to wait after page load completed
+        before tearing down, relative to the time it took to reach the page load
+        to complete.
     """
     for domain in self._domains_to_enable:
       self._ws.RegisterDomain(domain, self._OnDataReceived)
       if domain != self.TRACING_DOMAIN:
         self.SyncRequestNoResponse('%s.enable' % domain)
         # Tracing setup must be done by the tracing track to control filtering
         # and output.
     for scoped_state in self._scoped_states:
       self.SyncRequestNoResponse(scoped_state,
                                  self._scoped_states[scoped_state][0])
@@ skipping 13 matching lines @@
 
     Args:
       address_delayed_stop: Whether the MonitorUrl()'s stop_delay_multiplier
         should be addressed or not.
     """
     if self._stop_delay_multiplier == 0:
       self._StopMonitoringImmediately()
     elif self._monitoring_stop_timestamp is None:
       assert self._monitoring_start_timestamp is not None
       current_time = datetime.datetime.now()
-      stop_delay_duration = self._stop_delay_multiplier * (
-          current_time - self._monitoring_start_timestamp)
-      logging.info('Delaying monitoring stop for %ds',
-                   stop_delay_duration.total_seconds())
-      self._monitoring_stop_timestamp = current_time + stop_delay_duration
+      stop_delay_duration_seconds = self._stop_delay_multiplier * (
+          current_time - self._monitoring_start_timestamp).seconds

[pasko, 2016/11/14 13:21:27]

was it also assuming seconds before or something more fine-granular?

it it is rounded to seconds now, it might affect hypothetical noise to
hypothetical sandwich runs. WDYT?

[Benoit L, 2016/11/14 13:26:19]

It was seconds as well, but couldn't handle non-integer scaling factors.

+      logging.info('Delaying monitoring stop for %.1fs',
+                   stop_delay_duration_seconds)
+      self._monitoring_stop_timestamp = (
+          current_time + datetime.timedelta(
+              seconds=stop_delay_duration_seconds))
 
   def ExecuteJavaScript(self, expression):
     """Run JavaScript expression.
 
     Args:
       expression: JavaScript expression to run.
 
     Returns:
       The return value from the JavaScript expression.
     """
@@ skipping 189 matching lines @@
       json_data: (dict) Parsed from a JSON file using the json module.
 
     Returns:
       a Track instance.
     """
     # There is no sensible way to deserialize this abstract class, but
     # subclasses are not required to define a deserialization method. For
     # example, for testing we have a FakeRequestTrack which is never
     # deserialized; instead fake instances are deserialized as RequestTracks.
     assert False