Update notification: Add shown notification metric.

This CL adds the notification shown metrics for update notification,
which informs the user to update Chrome in play store.

Bug: 952354
Change-Id: Id0a6c1a944ec2bdadfc782926591e8b51d9a616c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1585233Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654667}

chrome/android/java/src/org/chromium/chrome/browser/omaha/UpdateNotificationController.java

@@ -26,6 +26,7 @@ import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.IntentHandler;
 import org.chromium.chrome.browser.document.ChromeLauncherActivity;
 import org.chromium.chrome.browser.lifecycle.Destroyable;
+import org.chromium.chrome.browser.notifications.ChromeNotification;
 import org.chromium.chrome.browser.notifications.ChromeNotificationBuilder;
 import org.chromium.chrome.browser.notifications.NotificationBuilderFactory;
 import org.chromium.chrome.browser.notifications.NotificationConstants;
@@ -126,8 +127,12 @@ public class UpdateNotificationController implements Destroyable {
                         .setContentText(getUpdateNotificationTextBody());
 
         builder.setContentIntent(createContentIntent(mUpdateStatus));
+        ChromeNotification notification = builder.buildChromeNotification();
         NotificationManagerProxy notificationManager = new NotificationManagerProxyImpl(mActivity);
-        notificationManager.notify(builder.buildChromeNotification());
+        notificationManager.notify(notification);
+        NotificationUmaTracker.getInstance().onNotificationShown(
+                NotificationUmaTracker.SystemNotificationType.UPDATES,
+                notification.getNotification());
         updateLastPushedTimeStamp();
     }