Update from https://crrev.com/333737

base/trace_event/process_memory_totals.cc

Index: base/trace_event/process_memory_totals.cc
diff --git a/base/trace_event/process_memory_totals.cc b/base/trace_event/process_memory_totals.cc
index 9b0c3776eea2aefae9f8bc050b68a04e5ba6b46b..1270924fbfbd0cf60cc5bab6b2554ac38c88eba3 100644
--- a/base/trace_event/process_memory_totals.cc
+++ b/base/trace_event/process_memory_totals.cc
@@ -11,9 +11,24 @@
 namespace base {
 namespace trace_event {
 
+ProcessMemoryTotals::ProcessMemoryTotals()
+    : resident_set_bytes_(0),
+      peak_resident_set_bytes_(0),
+      is_peak_rss_resetable_(false) {
+}
+
 void ProcessMemoryTotals::AsValueInto(TracedValue* value) const {
   value->SetString("resident_set_bytes",
                    StringPrintf("%" PRIx64, resident_set_bytes_));
+  if (peak_resident_set_bytes_ > 0) {
+    value->SetString("peak_resident_set_bytes",
+                     StringPrintf("%" PRIx64, peak_resident_set_bytes_));
+    value->SetBoolean("is_peak_rss_resetable", is_peak_rss_resetable_);
+  }
+}
+
+void ProcessMemoryTotals::Clear() {
+  resident_set_bytes_ = 0;
 }
 
 }  // namespace trace_event