Revert of Remove usages of Timeline commands in telemetry

tools/telemetry/telemetry/core/backends/chrome_inspector/inspector_backend.py

Index: tools/telemetry/telemetry/core/backends/chrome_inspector/inspector_backend.py
diff --git a/tools/telemetry/telemetry/core/backends/chrome_inspector/inspector_backend.py b/tools/telemetry/telemetry/core/backends/chrome_inspector/inspector_backend.py
index 8a4003d2d543d95e51a9d95581cc845243ad9f25..338f13a8eecfd4a4983b4f79b668a6dfdd20cb06 100644
--- a/tools/telemetry/telemetry/core/backends/chrome_inspector/inspector_backend.py
+++ b/tools/telemetry/telemetry/core/backends/chrome_inspector/inspector_backend.py
@@ -14,11 +14,13 @@
 from telemetry.core.backends.chrome_inspector import inspector_network
 from telemetry.core.backends.chrome_inspector import inspector_page
 from telemetry.core.backends.chrome_inspector import inspector_runtime
+from telemetry.core.backends.chrome_inspector import inspector_timeline
 from telemetry.core.backends.chrome_inspector import inspector_websocket
 from telemetry.core.backends.chrome_inspector import websocket
 from telemetry.core.heap import model as heap_model_module
 from telemetry.image_processing import image_util
 from telemetry.timeline import model as timeline_model_module
+from telemetry.timeline import recording_options
 from telemetry.timeline import trace_data as trace_data_module
 
 
@@ -51,6 +53,7 @@
     self._page = inspector_page.InspectorPage(
         self._websocket, timeout=timeout)
     self._runtime = inspector_runtime.InspectorRuntime(self._websocket)
+    self._timeline = inspector_timeline.InspectorTimeline(self._websocket)
     self._network = inspector_network.InspectorNetwork(self._websocket)
     self._timeline_model = None
 
@@ -176,17 +179,34 @@
   def timeline_model(self):
     return self._timeline_model
 
-  def StartTimelineRecording(self):
-    self._network.timeline_recorder.Start()
+  def StartTimelineRecording(self, options=None):
+    if not options:
+      options = recording_options.TimelineRecordingOptions()
+    if options.record_timeline:
+      self._timeline.Start()
+    if options.record_network:
+      self._network.timeline_recorder.Start()
 
   def StopTimelineRecording(self):
     builder = trace_data_module.TraceDataBuilder()
+
+    data = self._timeline.Stop()
+    if data:
+      builder.AddEventsTo(trace_data_module.INSPECTOR_TRACE_PART, data)
 
     data = self._network.timeline_recorder.Stop()
     if data:
       builder.AddEventsTo(trace_data_module.INSPECTOR_TRACE_PART, data)
-    self._timeline_model = timeline_model_module.TimelineModel(
-        builder.AsData(), shift_world_to_zero=False)
+
+    if builder.HasEventsFor(trace_data_module.INSPECTOR_TRACE_PART):
+      self._timeline_model = timeline_model_module.TimelineModel(
+          builder.AsData(), shift_world_to_zero=False)
+    else:
+      self._timeline_model = None
+
+  @property
+  def is_timeline_recording_running(self):
+    return self._timeline.is_timeline_recording_running
 
   # Network public methods.