[Telemetry] Adding Memory Timeline Metric

tools/telemetry/telemetry/timeline/model.py

Index: tools/telemetry/telemetry/timeline/model.py
diff --git a/tools/telemetry/telemetry/timeline/model.py b/tools/telemetry/telemetry/timeline/model.py
index a147d43df3625bb073993e13cecd87567cf2c5b5..85cf3c1d1513b67ce4ec09befba5a45996df2484 100644
--- a/tools/telemetry/telemetry/timeline/model.py
+++ b/tools/telemetry/telemetry/timeline/model.py
@@ -13,6 +13,7 @@ from telemetry.timeline import async_slice as async_slice_module
 from telemetry.timeline import bounds
 from telemetry.timeline import event_container
 from telemetry.timeline import inspector_importer
+from telemetry.timeline import memory_dump_event
 from telemetry.timeline import process as process_module
 from telemetry.timeline import slice as slice_module
 from telemetry.timeline import surface_flinger_importer
@@ -69,9 +70,37 @@ class TimelineModel(event_container.TimelineEventContainer):
     self.import_errors = []
     self.metadata = []
     self.flow_events = []
+    self._memory_dump_events = None
     if trace_data is not None:
       self.ImportTraces(trace_data, shift_world_to_zero=shift_world_to_zero)
 
+  def SetMemoryDumpEvents(self, memory_dump_events):
+    """Populates the model with a sequence of MemoryDumpEvent objects."""
+    assert not self._frozen and self._memory_dump_events is None
+    # keep events sorted in cronological order
+    self._memory_dump_events = sorted(memory_dump_events,
+                                      key=lambda event: event.start)
+
+  def IterMemoryDumpEvents(self, reverse=False):
+    """Iterate over the memory dump events of this model.
+
+    Args:
+      reverse: A boolean indicating whether to yield events in reversed time
+          order. By default events are generated in chronological order.
+    """
+    if self._memory_dump_events is None:
+      return iter([]) # empty iterator
+    elif reverse:
+      return reversed(self._memory_dump_events)
+    else:
+      return iter(self._memory_dump_events)
+
+  def IterEventsInThisContainer(self, event_type_predicate, event_predicate):
+    if event_type_predicate(memory_dump_event.MemoryDumpEvent):
+      for event in self.IterMemoryDumpEvents():
+        if event_predicate(event):
+          yield event
+
   def IterChildContainers(self):
     for process in self._processes.itervalues():
       yield process