Temporary commit to evaluate perf impact of prototype CPU profiler

base/profiler/cpu_profiler_posix.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/profiler/cpu_profiler.h"
+
+namespace base {
+
+CpuProfiler::CpuProfiler() {}
+
+CpuProfiler::~CpuProfiler() {}
+
+// static
+bool CpuProfiler::IsPlatformSupported() {
+  return false;
+}
+
+void CpuProfiler::OnTimer() {}
+
+void CpuProfiler::GetThreadIds() {}
+
+}