Update stopwatch to use patching to share sources instead of exposing

runtime/lib/clock.cc

Index: runtime/lib/clock.cc
diff --git a/runtime/lib/clock.cc b/runtime/lib/clock.cc
deleted file mode 100644
index 1a07623c4c9fb4d2de49d5ee3dcb16a3ddebffb2..0000000000000000000000000000000000000000
--- a/runtime/lib/clock.cc
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-#include "vm/bootstrap_natives.h"
-
-#include "vm/object.h"
-#include "vm/os.h"
-
-namespace dart {
-
-DEFINE_NATIVE_ENTRY(Clock_now, 0) {
-  // TODO(iposva): investigate other hi-res time sources such as cycle count.
-  const Integer& micros =
-      Integer::Handle(Integer::New(OS::GetCurrentTimeMicros()));
-  arguments->SetReturn(micros);
-}
-
-
-DEFINE_NATIVE_ENTRY(Clock_frequency, 0) {
-  // TODO(iposva): investigate other hi-res time sources such as cycle count.
-  const Integer& frequency = Integer::Handle(Integer::New(1000000));
-  arguments->SetReturn(frequency);
-}
-
-}  // namespace dart