[tracing] Ignore tracing allocations in heap profiler

base/trace_event/heap_profiler_scoped_ignore.cc

+// Copyright 2015 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.
+
+#include "base/trace_event/heap_profiler_scoped_ignore.h"
+
+namespace base {
+namespace trace_event {
+
+HeapProfilerScopedIgnore::HeapProfilerScopedIgnore() {}
+
+HeapProfilerScopedIgnore::~HeapProfilerScopedIgnore() {

[Primiano Tucci (use gerrit), 2016/04/21 19:47:32]

I'd just add a comment saying: 
The corresponding begin_ignore_scope is in the definition of
HEAP_PROFILER_SCOPED_IGNORE in the header.

[ssid, 2016/04/22 04:57:12]

Done.

+  if (UNLIKELY(AllocationContextTracker::capture_enabled())) {
+    AllocationContextTracker::GetInstanceForCurrentThread()->end_ignore_scope();
+  }
+}
+
+}  // namespace trace_event
+}  // namespace base