[tracing] Dump child processes' memory metrics in browser

components/tracing/process_metrics_memory_dump_provider.cc

Index: components/tracing/process_metrics_memory_dump_provider.cc
diff --git a/components/tracing/process_metrics_memory_dump_provider.cc b/components/tracing/process_metrics_memory_dump_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a1518d6a79bf0b38e9116f459eb9f6e9971ee359
--- /dev/null
+++ b/components/tracing/process_metrics_memory_dump_provider.cc
@@ -0,0 +1,78 @@
+// 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 "components/tracing/process_metrics_memory_dump_provider.h"
+
+#include "base/process/process_metrics.h"
+#include "base/trace_event/process_memory_dump.h"
+#include "base/trace_event/process_memory_totals.h"
+
+namespace tracing {
+
+namespace {
+
+base::ProcessMetrics* CreateProcessMetrics(base::ProcessHandle process) {
+  if (process == base::kNullProcessHandle)
+    process = base::GetCurrentProcessHandle();
+#if !defined(OS_MACOSX) || defined(OS_IOS)
+  return base::ProcessMetrics::CreateProcessMetrics(process);
+#else
+  return base::ProcessMetrics::CreateProcessMetrics(process, NULL);
+#endif
+}
+
+}  // namespace
+
+// static
+uint64 ProcessMetricsMemoryDumpProvider::rss_bytes_for_testing = 0;
+
+ProcessMetricsMemoryDumpProvider::ProcessMetricsMemoryDumpProvider(
+    base::ProcessHandle process)
+    : process_(process), process_metrics_(CreateProcessMetrics(process)) {}
+
+ProcessMetricsMemoryDumpProvider::~ProcessMetricsMemoryDumpProvider() {}
+
+// Called at trace dump point time. Creates a snapshot of the memory maps for
+// the current process.
+bool ProcessMetricsMemoryDumpProvider::OnMemoryDump(
+    const base::trace_event::MemoryDumpArgs& args,
+    base::trace_event::ProcessMemoryDump* pmd) {
+  DumpProcessTotals(args, pmd);
+
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+  DumpProcessMemoryMaps(args, pmd);
+#endif
+  return true;
+}
+
+#if !defined(OS_LINUX) && !defined(OS_ANDROID)
+void ProcessMetricsMemoryDumpProvider::DumpProcessTotals(
+    const base::trace_event::MemoryDumpArgs& args,
+    base::trace_event::ProcessMemoryDump* pmd) {
+  const uint64 rss_bytes = rss_bytes_for_testing
+                               ? rss_bytes_for_testing
+                               : process_metrics_->GetWorkingSetSize();
+
+  uint64 peak_rss_bytes = 0;
+
+#if !defined(OS_IOS)
+  peak_rss_bytes = process_metrics_->GetPeakWorkingSetSize();
+#if defined(MACOSX)
+  size_t private_bytes;
+  bool res = process_metrics_->GetMemoryBytes(&private_bytes,
+                                              nullptr /* shared_bytes */);
+  if (res) {
+    pmd->process_totals()->SetExtraFieldInBytes("private_bytes", private_bytes);
+  }
+#endif  // defined(MACOSX)
+#endif  // !defined(OS_IOS)
+
+  DCHECK(rss_bytes);
+  pmd->process_totals()->set_resident_set_bytes(rss_bytes);
+  pmd->process_totals()->set_peak_resident_set_bytes(peak_rss_bytes);
+  pmd->set_has_process_totals();
+}
+#endif  // !defined(OS_LINUX) && !defined(OS_ANDROID)
+
+}  // namespace tracing