[USS] Show USS counters in about:sync page

components/sync/driver/resources/about.js

Index: components/sync/driver/resources/about.js
diff --git a/components/sync/driver/resources/about.js b/components/sync/driver/resources/about.js
index 47c1ab9392aa340da1810351a8a6ece4dc367342..4c072524b6d8d79d7e8060eb51d38c02d2d0d5e1 100644
--- a/components/sync/driver/resources/about.js
+++ b/components/sync/driver/resources/about.js
@@ -28,6 +28,24 @@ cr.define('chrome.sync.about_tab', function() {
     jstProcess(new JsEvalContext(aboutInfo), aboutInfoDiv);
   }
 
+  function onAboutInfoCountersUpdated(e) {

[pavely, 2016/10/03 21:40:14]

Could you move this function below onAboutInfoUpdatedEvent.
onAboutInfoUpdatedEvent and refreshAboutInfo belong together as former calls
latter.

[Gang Wu, 2016/10/06 00:20:22]

Done.

+    var details = e.details;
+
+    var modelType = details.modelType;
+    var counters = details.counters;
+
+    var type_status_array = chrome.sync.aboutInfo.type_status;

[pavely, 2016/10/03 21:40:14]

onCountersUpdated can be called for different counter types. Do you need to
handle it here? Maybe it doesn't matter.

[Gang Wu, 2016/10/06 00:20:22]

I think it doesn't matter, just means update more.

+    type_status_array.forEach(function(row) {
+      if (row.name == modelType) {
+        row.num_entries = counters.numEntriesAndTombstones;
+        row.num_live = counters.numEntries;
+      }
+    });
+    jstProcess(
+        new JsEvalContext({ type_status: type_status_array }),
+        $('typeInfo'));
+  }
+
   function onAboutInfoUpdatedEvent(e) {
     refreshAboutInfo(e.details);
   }
@@ -143,6 +161,10 @@ cr.define('chrome.sync.about_tab', function() {
           'onAboutInfoUpdated',
           onAboutInfoUpdatedEvent);
 
+      chrome.sync.events.removeEventListener(
+          'onCountersUpdated',
+          onAboutInfoCountersUpdated);
+
       var aboutInfo = JSON.parse(data);
       refreshAboutInfo(aboutInfo);
     });
@@ -172,6 +194,10 @@ cr.define('chrome.sync.about_tab', function() {
         'onAboutInfoUpdated',
         onAboutInfoUpdatedEvent);
 
+    chrome.sync.events.addEventListener(
+        'onCountersUpdated',
+        onAboutInfoCountersUpdated);
+
     // Register to receive a stream of event notifications.
     chrome.sync.registerForEvents();