Add Breakpoint class to Observatory.

runtime/observatory/test/debugging_test.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 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 import 'dart:async';
 
 void testFunction() {
@@ skipping 39 matching lines @@
             expect(events[0].eventType, equals('BreakpointResolved'));
             expect(events[1].eventType, equals('BreakpointReached'));
             print('Breakpoint reached');
             completer.complete();
           }
         }
       });
 
       // Add the breakpoint.
       var script = isolate.rootLib.scripts[0];
-      return isolate.addBreakpoint(script, 14).then((ServiceObject bpt) {
-          expect(bpt is ServiceMap, isTrue);
-          ServiceMap m = bpt;
-          expect(m.type, equals('Breakpoint'));
-          expect(m['location']['script'].id, equals(script.id));
-          expect(m['location']['tokenPos'], equals(51));
+      return isolate.addBreakpoint(script, 14).then((result) {
+          expect(result is Breakpoint, isTrue);
+          Breakpoint bpt = result;
+          expect(bpt.type, equals('Breakpoint'));
+          expect(bpt.script.id, equals(script.id));
+          expect(bpt.tokenPos, equals(51));
           expect(isolate.breakpoints.length, equals(1));
           return completer.future;  // Wait for breakpoint events.
       });
     });
 },
 
 // Get the stack trace
 (Isolate isolate) {
   return isolate.getStack().then((ServiceMap stack) {
       expect(stack.type, equals('Stack'));
@@ skipping 34 matching lines @@
   expect(isolate.breakpoints.length, equals(1));
   var bpt = isolate.breakpoints[0];
   return isolate.removeBreakpoint(bpt).then((_) {
       expect(isolate.breakpoints.length, equals(0));
   });
 },
 
 ];
 
 main(args) => runIsolateTests(args, tests, testeeConcurrent: testFunction);