Observatory: Report peak process memory usage.

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

 <link rel="import" href="../../../../packages/polymer/polymer.html">
 <link rel="import" href="eval_box.html">
 <link rel="import" href="isolate_summary.html">
 
 <polymer-element name="vm-view">
   <template>
     <link rel="stylesheet" href="css/shared.css">
 
     <nav-bar>
       <top-nav-menu last="{{ false }}"></top-nav-menu>
@@ skipping 27 matching lines @@
           <div class="memberValue">{{ vm.upTime.toString() }}</div>
         </div>
         <div class="memberItem">
           <div class="memberName">refreshed at</div>
           <div class="memberValue">{{ vm.refreshTime.toString() }}</div>
         </div>
         <div class="memberItem">
           <div class="memberName">pid</div>
           <div class="memberValue">{{ vm.pid }}</div>
         </div>
+        <div class="memberItem">
+          <div class="memberName">peak memory</div>
+          <div class="memberValue">{{ vm.maxRSS }}</div>
+        </div>
         <br>
         <div class="memberItem">
           <div class="memberValue">
             See <a on-click="{{ goto }}" _href="{{ gotoLink('/flags') }}">flags</a>
           </div>
           <div class="memberValue">
             View <a on-click="{{ goto }}" _href="{{ gotoLink('/timeline') }}">timeline</a>
           </div>
         </div>
       </div>
       <br>
       <br>
       <h1>Isolates ({{ vm.isolates.length }})</h1>
       <hr>
       <ul class="list-group">
         <template repeat="{{ isolate in vm.isolates }}">
           <li class="list-group-item">
             <isolate-summary isolate="{{ isolate }}"></isolate-summary>
           </li>
           <hr>
         </template>
       </ul>
     </div>
     <view-footer></view-footer>
   </template>
 </polymer-element>
 
 <script type="application/dart" src="vm_view.dart"></script>