Avoid to list internal Arrays in _GetRetainingPath api

runtime/observatory/lib/src/elements/object_common.html

Index: runtime/observatory/lib/src/elements/object_common.html
diff --git a/runtime/observatory/lib/src/elements/object_common.html b/runtime/observatory/lib/src/elements/object_common.html
index 0235248ff5213e1e6dd15f159b896a008bd075dc..299470c208db6aa89740dcf12e7305971830e8d1 100644
--- a/runtime/observatory/lib/src/elements/object_common.html
+++ b/runtime/observatory/lib/src/elements/object_common.html
@@ -65,7 +65,7 @@
             </template>
             <template repeat="{{ element in path['elements'] }}">
             <div class="memberItem">
-              <div class="memberName">[{{ element['index']}}]</div>
+              <div class="memberName">[{{ path['elements'].indexOf(element) }}]</div>
               <div class="memberValue">
                 <template if="{{ element['parentField'] != null }}">
                   from <any-service-ref ref="{{ element['parentField'] }}"></any-service-ref> of
@@ -73,6 +73,9 @@
                 <template if="{{ element['parentListIndex'] != null }}">
                   from [{{ element['parentListIndex'] }}] of
                 </template>
+                <template if="{{ element['parentMapKey'] != null }}">
+                  from [<any-service-ref ref="{{ element['parentMapKey'] }}"></any-service-ref>] of
+                </template>
                 <template if="{{ element['_parentWordOffset'] != null }}">
                   from word[{{ element['_parentWordOffset'] }}] of
                 </template>