Fix many warnings/errors when building Observatory

runtime/observatory/lib/src/models/objects/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 models;
 
 enum ProfileTreeDirection { inclusive, exclusive }
 
 abstract class SampleProfile {
   int get sampleCount;
@@ skipping 35 matching lines @@
   CodeCallTree filtered(CallTreeNodeFilter filter);
 }
 
 abstract class FunctionCallTree extends CallTree {
   FunctionCallTreeNode get root;
   FunctionCallTree filtered(CallTreeNodeFilter filter);
 }
 
 abstract class CallTreeNode {
   double get percentage;
+  int get inclusiveNativeAllocations;
+  int get exclusiveNativeAllocations;
   Iterable<CallTreeNode> get children;
 }
 
 abstract class CodeCallTreeNode extends CallTreeNode {
   ProfileCode get profileCode;
   Iterable<CodeCallTreeNode> get children;
 }
 
 abstract class FunctionCallTreeNode extends CallTreeNode {
   ProfileFunction get profileFunction;
   Iterable<FunctionCallTreeNode> get children;
 }