Fix code coverage (again!)

runtime/bin/vmservice/client/lib/src/service/object.dart

 // Copyright (c) 2014, 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 service;
 
 /// A [ServiceObject] is an object known to the VM service and is tied
 /// to an owning [Isolate].
 abstract class ServiceObject extends Observable {
   /// The owner of this [ServiceObject].  This can be an [Isolate], a
@@ skipping 1091 matching lines @@
     fields.addAll(map['fields']);
 
     functions.clear();
     functions.addAll(map['functions']);
 
     superClass = map['super'];
     if (superClass != null) {
       superClass._addToChildren(this);
     }
     error = map['error'];
-    
+
     var allocationStats = map['allocationStats'];
     if (allocationStats != null) {
       newSpace.update(allocationStats['new']);
       oldSpace.update(allocationStats['old']);
     }
   }
 
   void _addToChildren(Class cls) {
     if (children.contains(cls)) {
       return;
     }
     children.add(cls);
   }
-  
+
   Future<ServiceObject> get(String command) {
     return isolate.get(id + "/$command");
   }
 }
 
 class ScriptLine extends Observable {
   final int line;
   final String text;
   @observable int hits;
   ScriptLine(this.line, this.text);
@@ skipping 63 matching lines @@
               lastTokenPos : tokenOffset;
         }
         _tokenToLine[tokenOffset] = lineNumber;
         _tokenToCol[tokenOffset] = colNumber;
       }
     }
   }
 
   void _processHits(List scriptHits) {
     // Update hits table.
-    _hits.clear();
     for (var i = 0; i < scriptHits.length; i += 2) {
       var line = scriptHits[i];
       var hit = scriptHits[i + 1]; // hit status.
       assert(line >= 1); // Lines start at 1.
+      var oldHits = _hits[line];
+      if (oldHits != null) {
+        hit += oldHits;
+      }
       _hits[line] = hit;
     }
     _applyHitsToLines();
   }
 
   void _processSource(String source) {
     // Preemptyively mark that this is not loaded.
     _loaded = false;
     if (source == null) {
       return;
@@ skipping 599 matching lines @@
     var v = list[i];
     if ((v is ObservableMap) && _isServiceMap(v)) {
       list[i] = owner.getFromMap(v);
     } else if (v is ObservableList) {
       _upgradeObservableList(v, owner);
     } else if (v is ObservableMap) {
       _upgradeObservableMap(v, owner);
     }
   }
 }