Update from https://crrev.com/318214

base/trace_event/process_memory_dump.cc

Index: base/trace_event/process_memory_dump.cc
diff --git a/base/trace_event/process_memory_dump.cc b/base/trace_event/process_memory_dump.cc
index 6da9132cf774c225976cacd3f69fe4eff6db1b5d..5363db559c32151712dc128e74d44f1933bbec00 100644
--- a/base/trace_event/process_memory_dump.cc
+++ b/base/trace_event/process_memory_dump.cc
@@ -10,7 +10,8 @@
 namespace base {
 namespace trace_event {
 
-ProcessMemoryDump::ProcessMemoryDump() : has_process_totals_(false) {
+ProcessMemoryDump::ProcessMemoryDump()
+    : has_process_totals_(false), has_process_mmaps_(false) {
 }
 
 ProcessMemoryDump::~ProcessMemoryDump() {
@@ -23,6 +24,11 @@ void ProcessMemoryDump::AsValueInto(TracedValue* value) const {
     process_totals_.AsValueInto(value);
     value->EndDictionary();
   }
+  if (has_process_mmaps_) {
+    value->BeginDictionary("process_mmaps");
+    process_mmaps_.AsValueInto(value);
+    value->EndDictionary();
+  }
 }
 
 }  // namespace trace_event