Revert of Revert of Add explicit support for discovering the GpuProcess to Telemetry's 'Model'.

tools/telemetry/telemetry/timeline/model.py

 # Copyright 2014 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.
 '''A container for timeline-based events and traces and can handle importing
 raw event data from different sources. This model closely resembles that in the
 trace_viewer project:
 https://code.google.com/p/trace-viewer/
 '''
 
 from operator import attrgetter
@@ skipping 44 matching lines @@
     Args:
         trace_data: trace_data.TraceData containing events to import
         shift_world_to_zero: If true, the events will be shifted such that the
             first event starts at time 0.
     """
     super(TimelineModel, self).__init__(name='TimelineModel', parent=None)
     self._bounds = bounds.Bounds()
     self._thread_time_bounds = {}
     self._processes = {}
     self._browser_process = None
+    self._gpu_process = None
     self._surface_flinger_process = None
     self._frozen = False
     self._tab_ids_to_renderer_threads_map = {}
     self.import_errors = []
     self.metadata = []
     self.flow_events = []
     if trace_data is not None:
       self.ImportTraces(trace_data, shift_world_to_zero=shift_world_to_zero)
 
   def IterChildContainers(self):
@@ skipping 22 matching lines @@
   def browser_process(self):
     return self._browser_process
 
   @browser_process.setter
   #pylint: disable=E0202
   def browser_process(self, browser_process):
     self._browser_process = browser_process
 
   @property
   #pylint: disable=E0202
+  def gpu_process(self):
+    return self._gpu_process
+
+  @gpu_process.setter
+  #pylint: disable=E0202
+  def gpu_process(self, gpu_process):
+    self._gpu_process = gpu_process
+
+  @property
+  #pylint: disable=E0202
   def surface_flinger_process(self):
     return self._surface_flinger_process
 
   @surface_flinger_process.setter
   #pylint: disable=E0202
   def surface_flinger_process(self, surface_flinger_process):
     self._surface_flinger_process = surface_flinger_process
 
   def AddMappingFromTabIdToRendererThread(self, tab_id, renderer_thread):
     if self._frozen:
@@ skipping 136 matching lines @@
     importers = []
     for part in trace_data.active_parts:
       importer_class = FindImporterClassForPart(part)
       if not importer_class:
         raise Exception('No importer found for %s' % repr(part))
       importers.append(importer_class(self, trace_data))
 
       importers.sort(key=lambda k: k.import_order)
 
     return importers