Add more timing information in the VM to track time spent is dart code Vs native code.

runtime/lib/isolate.cc

 // Copyright (c) 2012, 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 "platform/assert.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
@@ skipping 91 matching lines @@
   args.SetAt(0, message);
   Exceptions::ThrowByType(Exceptions::kIsolateSpawn, args);
 }
 
 
 static bool CanonicalizeUri(Isolate* isolate,
                             const Library& library,
                             const String& uri,
                             char** canonical_uri,
                             char** error) {
+  VmToNativeTimerScope timer(isolate);
   Zone* zone = isolate->current_zone();
   bool retval = false;
   Dart_LibraryTagHandler handler = isolate->library_tag_handler();
   if (handler != NULL) {
     Dart_EnterScope();
     Dart_Handle result = handler(Dart_kCanonicalizeUrl,
                                  Api::NewHandle(isolate, library.raw()),
                                  Api::NewHandle(isolate, uri.raw()));
     const Object& obj = Object::Handle(Api::UnwrapHandle(result));
     if (obj.IsString()) {
@@ skipping 123 matching lines @@
 
   // The control port is being accessed as a regular port from Dart code. This
   // is most likely due to the _startIsolate code in dart:isolate. Account for
   // this by increasing the number of open control ports.
   isolate->message_handler()->increment_control_ports();
 
   return port.raw();
 }
 
 }  // namespace dart