Added MemoryMonitor for Linux (with test)

components/memory_coordinator/browser/test_memory_monitor.cc

Index: components/memory_coordinator/browser/test_memory_monitor.cc
diff --git a/components/memory_coordinator/browser/test_memory_monitor.cc b/components/memory_coordinator/browser/test_memory_monitor.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d17e768babe2a4d05de281f12c9c7c64c011991f
--- /dev/null
+++ b/components/memory_coordinator/browser/test_memory_monitor.cc
@@ -0,0 +1,17 @@
+// Copyright (c) 2016 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/memory_coordinator/browser/test_memory_monitor.h"
+
+namespace memory_coordinator {
+
+TestMemoryMonitorDelegate::~TestMemoryMonitorDelegate() {}
+
+void TestMemoryMonitorDelegate::GetSystemMemoryInfo(
+    base::SystemMemoryInfoKB* mem_info) {
+  *mem_info = mem_info_;
+  ++calls_;
+}
+
+}  // namespace memory_coordinator