Remove usages of Timeline commands in telemetry

tools/chrome_proxy/integration_tests/network_metrics.py

Index: tools/chrome_proxy/integration_tests/network_metrics.py
diff --git a/tools/chrome_proxy/integration_tests/network_metrics.py b/tools/chrome_proxy/integration_tests/network_metrics.py
index 747d60dfb2a7a12f860db5b433682e0cbcbfd94e..9c41dcce37d83164f4e227a54418ff52e1ed40a6 100644
--- a/tools/chrome_proxy/integration_tests/network_metrics.py
+++ b/tools/chrome_proxy/integration_tests/network_metrics.py
@@ -13,7 +13,6 @@ from metrics import Metric
 from telemetry.page import page_test
 # All network metrics are Chrome only for now.
 from telemetry.core.backends.chrome_inspector import inspector_network
-from telemetry.timeline import recording_options
 from telemetry.value import scalar
 
 
@@ -138,9 +137,7 @@ class NetworkMetric(Metric):
 
   def Start(self, page, tab):
     self._events = None
-    opts = recording_options.TimelineRecordingOptions()
-    opts.record_network = True
-    tab.StartTimelineRecording(opts)
+    tab.StartTimelineRecording()
 
   def Stop(self, page, tab):
     assert self._events is None