Revert of [telemetry] Add a V8GCTimes measurement and benchmarks.

tools/telemetry/telemetry/web_perf/metrics/v8_stats.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.
+
+class EventStats(object):
+  def __init__(self, src_event_name, result_name, result_description):
+    self.src_event_name = src_event_name
+    self.result_name = result_name
+    self.result_description = result_description
+    self.thread_duration = 0.0
+    self.thread_duration_inside_idle = 0.0
+
+  @property
+  def thread_duration_outside_idle(self):
+    return self.thread_duration - self.thread_duration_inside_idle
+
+
+def _FindEventStats(event_stats_list, event_name):
+  for event_stats in event_stats_list:
+    if event_stats.src_event_name == event_name:
+      return event_stats
+  return None
+
+
+def _IsDescendentOfIdleNotification(event):
+  parent = event.parent_slice
+  while parent:
+    if parent.name == 'V8.GCIdleNotification':
+      return True
+    parent = parent.parent_slice
+  return False
+
+class V8Stats(object):
+  def __init__(self, renderer_thread, interaction_records):
+    self.all_event_stats = [
+        EventStats('V8.GCIncrementalMarking',
+                   'incremental_marking',
+                   'total thread duration spent in incremental marking steps'),
+        EventStats('V8.GCScavenger',
+                   'scavenger',
+                   'total thread duration spent in scavenges'),
+        EventStats('V8.GCCompactor',
+                   'mark_compactor',
+                   'total thread duration spent in mark-sweep-compactor')]
+
+    # Find all GC events contained in an interaction record
+    for event in renderer_thread.IterAllSlices():
+      event_stats = _FindEventStats(self.all_event_stats, event.name)
+      if not event_stats:
+        continue
+      for r in interaction_records:
+        if not r.GetBounds().ContainsInterval(event.start, event.end):
+          continue
+        event_stats.thread_duration += event.thread_duration
+        if _IsDescendentOfIdleNotification(event):
+          event_stats.thread_duration_inside_idle += event.thread_duration
+
+  @property
+  def total_gc_thread_duration(self):
+    return sum(x.thread_duration for x in self.all_event_stats)
+
+  @property
+  def total_gc_thread_duration_outside_idle(self):
+    return sum(x.thread_duration_outside_idle for x in self.all_event_stats)