Display average time between collections

runtime/bin/vmservice/client/lib/src/elements/heap_profile.html

 <link rel="import" href="../../../../packages/polymer/polymer.html">
 <link rel="import" href="class_ref.html">
 <link rel="import" href="observatory_element.html">
 <link rel="import" href="nav_bar.html">
 
 <polymer-element name="heap-profile" extends="observatory-element">
 <template>
   <link rel="stylesheet" href="css/shared.css">
   <style>
     .table {
@@ skipping 71 matching lines @@
               {{ isolate.newSpace.capacity | formatSize }}
             </div>
           </div>
           <div class="memberItem">
             <div class="memberName">external</div>
             <div class="memberValue">
               {{ isolate.newSpace.external | formatSize }}
             </div>
           </div>
           <div class="memberItem">
-            <div class="memberName">Collections</div>
+            <div class="memberName">collections</div>
             <div class="memberValue">{{ formattedCollections(true) }}</div>
           </div>
           <div class="memberItem">
-            <div class="memberName">Average Collection Time</div>
+            <div class="memberName">average collection time</div>
             <div class="memberValue">{{ formattedAverage(true) }}</div>
           </div>
           <div class="memberItem">
-            <div class="memberName">Cumulative Collection Time</div>
+            <div class="memberName">cumulative collection time</div>
             <div class="memberValue">{{ formattedTotalCollectionTime(true) }}</div>
           </div>
+          <div class="memberItem">
+            <div class="memberName">average time between collections</div>
+            <div class="memberValue">{{ isolate.newSpace.averageCollectionPeriodInMillis.toStringAsFixed(2) }} ms</div>
+          </div>
         </div>
         <div id="newPieChart" style="height: 300px"></div>
       </div>
       <div id="oldSpace" class="flex-item-50-percent">
         <h2>Old Generation</h2>
         <br>
         <div class="memberList">
           <div class="memberItem">
             <div class="memberName">used</div>
             <div class="memberValue">
               {{ isolate.oldSpace.used | formatSize }}
               of
               {{ isolate.oldSpace.capacity | formatSize }}
             </div>
           </div>
           <div class="memberItem">
             <div class="memberName">external</div>
             <div class="memberValue">
               {{ isolate.oldSpace.external | formatSize }}
             </div>
           </div>
           <div class="memberItem">
-            <div class="memberName">Collections</div>
+            <div class="memberName">collections</div>
             <div class="memberValue">{{ formattedCollections(false) }}</div>
           </div>
           <div class="memberItem">
-            <div class="memberName">Average Collection Time</div>
+            <div class="memberName">average collection time</div>
             <div class="memberValue">{{ formattedAverage(false) }}</div>
           </div>
           <div class="memberItem">
-            <div class="memberName">Cumulative Collection Time</div>
+            <div class="memberName">cumulative collection time</div>
             <div class="memberValue">{{ formattedTotalCollectionTime(false) }}</div>
           </div>
+          <div class="memberItem">
+            <div class="memberName">average time between collections</div>
+            <div class="memberValue">{{ isolate.oldSpace.averageCollectionPeriodInMillis.toStringAsFixed(2) }} ms</div>
+          </div>
         </div>
         <div id="oldPieChart" style="height: 300px"></div>
       </div>
     </div>
   </div>
   <br>
   <hr>
   <div class="content-centered-big">
     <table id="classtable" class="flex-item-100-percent table">
       <thead id="classTableHead">
@@ skipping 14 matching lines @@
       <tbody id="classTableBody">
       </tbody>
     </table>
     <br><br><br>
     <br><br><br>
   </div>
 </template>
 </polymer-element>
 
 <script type="application/dart" src="heap_profile.dart"></script>