Fix many warnings/errors when building Observatory

runtime/observatory/lib/src/repositories/sample_profile.dart

 // Copyright (c) 2016, 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 repositories;
 
 String _tagToString(M.SampleProfileTag tag) {
   switch (tag) {
     case M.SampleProfileTag.userVM:
       return 'UserVM';
@@ skipping 14 matching lines @@
   final SampleProfileLoadingProgress progress;
   SampleProfileLoadingProgressEvent(this.progress);
 }
 
 class SampleProfileLoadingProgress extends M.SampleProfileLoadingProgress {
   StreamController<SampleProfileLoadingProgressEvent> _onProgress =
       new StreamController<SampleProfileLoadingProgressEvent>.broadcast();
   Stream<SampleProfileLoadingProgressEvent> get onProgress =>
       _onProgress.stream;
 
-  final ServiceObjectOwner owner;
+  final M.ServiceObjectOwner owner;
   final S.Class cls;
   final M.SampleProfileTag tag;
   final bool clear;
   final M.SampleProfileType type;
 
   M.SampleProfileLoadingStatus _status = M.SampleProfileLoadingStatus.fetching;
   double _progress = 0.0;
   final Stopwatch _fetchingTime = new Stopwatch();
   final Stopwatch _loadingTime = new Stopwatch();
   CpuProfile _profile;
@@ skipping 121 matching lines @@
     assert(cls != null);
     return cls.setTraceAllocations(false);
   }
 }
 
 class NativeMemorySampleProfileRepository
     implements M.NativeMemorySampleProfileRepository {
   SampleProfileLoadingProgress _last;
 
   Stream<SampleProfileLoadingProgressEvent> get(M.VM vm, M.SampleProfileTag t,
-      {bool forceFetch: false}) {
+      {bool forceFetch: false, bool clear: false}) {
     assert(forceFetch != null);
     if ((_last != null) && !forceFetch) {
       _last.reuse();
     } else {
       _last = new SampleProfileLoadingProgress(vm, t, false,
           type: M.SampleProfileType.memory);
     }
     return _last.onProgress;
   }
 }