Display average time between collections

runtime/bin/vmservice/client/deployed/web/index_devtools.html

Index: runtime/bin/vmservice/client/deployed/web/index_devtools.html
diff --git a/runtime/bin/vmservice/client/deployed/web/index_devtools.html b/runtime/bin/vmservice/client/deployed/web/index_devtools.html
index 48f835d18d7d8aa2c42a562abccb72cf51d1a1b0..6e13811f31ed87e7ad1fcc8c5cc5e2bb50070a72 100644
--- a/runtime/bin/vmservice/client/deployed/web/index_devtools.html
+++ b/runtime/bin/vmservice/client/deployed/web/index_devtools.html
@@ -14312,17 +14312,21 @@ hr {
             </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>
@@ -14345,17 +14349,21 @@ hr {
             </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>
@@ -16544,4 +16552,4 @@ hr {
 
   <observatory-application devtools="true"></observatory-application>
 
-<script type="application/dart" src="index_devtools.html_bootstrap.dart"></script><script src="packages/browser/dart.js"></script></body></html>
+<script src="index_devtools.html_bootstrap.dart.js"></script></body></html>