telemetry: Add thread time to telmetry timeline.

tools/telemetry/telemetry/core/timeline/event.py

Index: tools/telemetry/telemetry/core/timeline/event.py
diff --git a/tools/telemetry/telemetry/core/timeline/event.py b/tools/telemetry/telemetry/core/timeline/event.py
index 8b9db4cef72e082401be71fb0bf9ab3f32b591b9..916d540eabe8d2bdab06a28ef2d762c0ae71e980 100644
--- a/tools/telemetry/telemetry/core/timeline/event.py
+++ b/tools/telemetry/telemetry/core/timeline/event.py
@@ -3,26 +3,50 @@
 # found in the LICENSE file.
 
 class TimelineEvent(object):
-  """Represents a timeline event."""
-  def __init__(self, category, name, start, duration, args=None):
+  """Represents a timeline event.
+
+     thread_start, thread_duration and thread_end are the start time, duration
+     and end time of this event as measured by the thread-specific CPU clock
+     (ticking when the thread is actually scheduled). Thread time is optional
+     on trace events and the corresponding attributes in TimelineEvent will be
+     set to None (not 0) if not present. Users of this class need to properly
+     handle this case.
+  """
+  def __init__(self, category, name, start, duration, thread_start=None,
+               thread_duration=None, args=None):
     self.category = category
     self.name = name
     self.start = start
     self.duration = duration
+    self.thread_start = thread_start
+    self.thread_duration = thread_duration
     self.args = args
 
   @property
   def end(self):
     return self.start + self.duration
 
+  @property
+  def thread_end(self):
+    """Thread-specific CPU time when this event ended.
+
+       May be None if the trace event didn't have thread time data.
+    """
+    if self.thread_start == None or self.thread_duration == None:
+      return None
+    return self.thread_start + self.thread_duration
+
   def __repr__(self):
     if self.args:
       args_str = ', ' + repr(self.args)
     else:
       args_str = ''
 
-    return "TimelineEvent(name='%s', start=%f, duration=%s%s)" % (
-      self.name,
-      self.start,
-      self.duration,
-      args_str)
+    return ("TimelineEvent(name='%s', start=%f, duration=%s, " +
+            "thread_start=%s, thread_duration=%s%s)") % (
+                self.name,
+                self.start,
+                self.duration,
+                self.thread_start,
+                self.thread_duration,
+                args_str)