add sendRequest to VMIsolateRef

lib/src/isolate.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:async/async.dart';
 import 'package:crypto/crypto.dart';
 import 'package:json_rpc_2/json_rpc_2.dart' as rpc;
@@ skipping 246 matching lines @@
       var response = await _scope.sendRequest(
           "addBreakpointWithScriptUri", params);
       return newVMBreakpoint(_scope, response);
     } on rpc.RpcException catch (error) {
       // Error 102 indicates that the breakpoint couldn't be created.
       if (error.code == 102) return null;
       rethrow;
     }
   }
 
+  /// Makes a raw RPC to a VM service extension registered in the isolate
+  /// corresponding to the ID [number].
+  ///
+  /// [method] must correspond to a VM service extension installed on the VM
+  /// isolate and it must begin with prefix "ext.".
+  ///
+  /// [params] are passed to the extension handler and must be serializable to
+  /// a JSON string.
+  Future<Map> invokeExtension(String method, [Map<String, Object> params]) {
+    if (!method.startsWith('ext.')) {
+      throw new ArgumentError.value(method, 'method',
+          'must begin with "ext." prefix');
+    }
+    return _scope.sendRequest(method, params);
+  }
+
   bool operator ==(other) => other is VMIsolateRef &&
       other._scope.isolateId == _scope.isolateId;
 
   int get hashCode => _scope.isolateId.hashCode;
 
   String toString() => name;
 }
 
 /// A full isolate on the remote VM.
 class VMIsolate extends VMIsolateRef {
@@ skipping 81 matching lines @@
 
   /// The isolate continues until it exits the current function.
   static const out = const VMStep._("Out");
 
   /// The string name of the step type.
   final String _value;
 
   const VMStep._(this._value);
 
   String toString() => _value;
-}
+}