telemetry: Add GetRendererProcessFromTab to timeline model.

tools/telemetry/telemetry/core/timeline/model.py

Index: tools/telemetry/telemetry/core/timeline/model.py
diff --git a/tools/telemetry/telemetry/core/timeline/model.py b/tools/telemetry/telemetry/core/timeline/model.py
index 5efddd3aca113ede2a740c372079c67dca183d48..61ab315f968555387683dce9881d21b961c48604 100644
--- a/tools/telemetry/telemetry/core/timeline/model.py
+++ b/tools/telemetry/telemetry/core/timeline/model.py
@@ -10,6 +10,8 @@ https://code.google.com/p/trace-viewer/
 from operator import attrgetter
 
 import telemetry.core.timeline.process as tracing_process
+from telemetry.core import web_contents
+from telemetry.core import browser
 
 # Register importers for data
 from telemetry.core.timeline import inspector_importer
@@ -41,6 +43,7 @@ class TimelineModel(object):
     self._frozen = False
     self.import_errors = []
     self.metadata = []
+    self._core_object_to_timeline_container_map = {}
 
     if event_data is not None:
       self.ImportTraces([event_data], shift_world_to_zero=shift_world_to_zero)
@@ -168,6 +171,18 @@ class TimelineModel(object):
 
     return events
 
+  def GetRendererProcessFromTab(self, tab):
+    return self._core_object_to_timeline_container_map[tab]
+
+  def AddCoreObjectToContainerMapping(self, core_object, container):
+    """ Add a mapping from a core object to a timeline container.
+
+    Used for example to map a Tab to its renderer process in the timeline model.
+    """
+    assert(isinstance(core_object, web_contents.WebContents) or
+           isinstance(core_object, browser.Browser))
+    self._core_object_to_timeline_container_map[core_object] = container
+
   def _CreateImporter(self, event_data):
     for importer_class in _IMPORTERS:
       if importer_class.CanImport(event_data):