Properly split dart:_vmservice across sdk and runtime

runtime/lib/vmservice/running_isolates.dart

-// Copyright (c) 2013, 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.
-
-part of vmservice;
-
-class RunningIsolates implements MessageRouter {
-  final Map<int, RunningIsolate> isolates = new Map<int, RunningIsolate>();
-  int _rootPortId;
-
-  RunningIsolates();
-
-  void isolateStartup(int portId, SendPort sp, String name) {
-    if (_rootPortId == null) {
-      _rootPortId = portId;
-    }
-    var ri = new RunningIsolate(portId, sp, name);
-    isolates[portId] = ri;
-  }
-
-  void isolateShutdown(int portId, SendPort sp) {
-    if (_rootPortId == portId) {
-      _rootPortId = null;
-    }
-    isolates.remove(portId);
-  }
-
-  Future<String> route(Message message) {
-    String isolateParam = message.params['isolateId'];
-    int isolateId;
-    if (!isolateParam.startsWith('isolates/')) {
-      message.setErrorResponse(
-          kInvalidParams, "invalid 'isolateId' parameter: $isolateParam");
-      return message.response;
-    }
-    isolateParam = isolateParam.substring('isolates/'.length);
-    if (isolateParam == 'root') {
-      isolateId = _rootPortId;
-    } else {
-      try {
-        isolateId = int.parse(isolateParam);
-      } catch (e) {
-        message.setErrorResponse(
-            kInvalidParams, "invalid 'isolateId' parameter: $isolateParam");
-        return message.response;
-      }
-    }
-    var isolate = isolates[isolateId];
-    if (isolate == null) {
-      // There is some chance that this isolate may have lived before,
-      // so return a sentinel rather than an error.
-      var result = {
-        'type' : 'Sentinel',
-        'kind' : 'Collected',
-        'valueAsString' : '<collected>',
-      };
-      message.setResponse(encodeResult(message, result));
-      return message.response;
-    }
-    return isolate.route(message);
-  }
-}