Move malloc/partition_alloc memory usage functions to base

third_party/WebKit/Source/platform/wtf/ProcessMetrics.h

Index: third_party/WebKit/Source/platform/wtf/ProcessMetrics.h
diff --git a/third_party/WebKit/Source/platform/wtf/ProcessMetrics.h b/third_party/WebKit/Source/platform/wtf/ProcessMetrics.h
new file mode 100644
index 0000000000000000000000000000000000000000..c624dd3ab7b5f08dc2158add755c49e3cf9e3d42
--- /dev/null
+++ b/third_party/WebKit/Source/platform/wtf/ProcessMetrics.h
@@ -0,0 +1,20 @@
+// Copyright (c) 2017 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.
+
+#ifndef ProcessMetrics_h
+#define ProcessMetrics_h
+
+#include "base/process/process_metrics.h"
+
+namespace WTF {
+
+size_t GetMallocUsage() {
+  std::unique_ptr<base::ProcessMetrics> metric(
+      base::ProcessMetrics::CreateCurrentProcessMetrics());
+  return metric->GetMallocUsage();
+}
+
+}  // namespace WTF
+
+#endif  // ProcessMetrics_h