Update from https://crrev.com/327068

base/trace_event/memory_dump_session_state.h

Index: base/trace_event/memory_dump_session_state.h
diff --git a/base/trace_event/memory_dump_session_state.h b/base/trace_event/memory_dump_session_state.h
new file mode 100644
index 0000000000000000000000000000000000000000..38a6fe20d706710ad7b9070b8be3c8a349739222
--- /dev/null
+++ b/base/trace_event/memory_dump_session_state.h
@@ -0,0 +1,31 @@
+// 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.
+
+#ifndef BASE_TRACE_EVENT_MEMORY_DUMP_SESSION_STATE_H_
+#define BASE_TRACE_EVENT_MEMORY_DUMP_SESSION_STATE_H_
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/memory/ref_counted.h"
+#include "base/trace_event/memory_allocator_attributes_type_info.h"
+
+namespace base {
+namespace trace_event {
+
+class BASE_EXPORT MemoryDumpSessionState
+    : public RefCountedThreadSafe<MemoryDumpSessionState> {
+ public:
+  MemoryDumpSessionState();
+  MemoryAllocatorAttributesTypeInfo allocators_attributes_type_info;
+
+ private:
+  friend class RefCountedThreadSafe<MemoryDumpSessionState>;
+  ~MemoryDumpSessionState();
+};
+
+}  // namespace trace_event
+}  // namespace base
+
+#endif  // BASE_TRACE_EVENT_MEMORY_DUMP_SESSION_STATE_H_