Update from https://crrev.com/333737

base/trace_event/memory_allocator_dump_guid.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/memory_allocator_dump_guid.h"
+
+#include "base/format_macros.h"
+#include "base/hash.h"
+#include "base/strings/stringprintf.h"
+
+namespace base {
+namespace trace_event {
+
+MemoryAllocatorDumpGuid::MemoryAllocatorDumpGuid(uint64 guid) : guid_(guid) {
+}
+
+MemoryAllocatorDumpGuid::MemoryAllocatorDumpGuid()
+    : MemoryAllocatorDumpGuid(0u) {
+}
+
+MemoryAllocatorDumpGuid::MemoryAllocatorDumpGuid(const std::string& guid_str)
+    : MemoryAllocatorDumpGuid(Hash(guid_str)) {
+}
+
+std::string MemoryAllocatorDumpGuid::ToString() const {
+  return StringPrintf("%" PRIx64, guid_);
+}
+
+}  // namespace trace_event
+}  // namespace base