[tracing] Add a dump provider to dump process memory totals.

base/trace_event/process_memory_dump.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/process_memory_dump.h"
 
 #include "base/json/json_writer.h"
+#include "base/trace_event/process_memory_totals.h"
 #include "base/values.h"
 
 namespace base {
 namespace trace_event {
 
 ProcessMemoryDump::ProcessMemoryDump() {
 }
 
 ProcessMemoryDump::~ProcessMemoryDump() {
 }
 
+void ProcessMemoryDump::SetProcessTotals(scoped_ptr<ProcessMemoryTotals> pmt) {
+  process_totals_ = pmt.Pass();
+}
+
 void ProcessMemoryDump::AppendAsTraceFormat(std::string* out) const {
   // Build up the [dumper name] -> [serialized snapshot] JSON dictionary.
   DictionaryValue dict;
   std::string json_dict;
-  // TODO(primiano): this will append here the actual dumps from the dumpers.
+
+  if (process_totals_)
+    dict.Set("process_totals", process_totals_->AsValue());
+
   base::JSONWriter::Write(&dict, &json_dict);
   *out += json_dict;
 }
 
 }  // namespace trace_event
 }  // namespace base