[FCM] Delete persisted message when token gets deleted

Bug: 882887
Change-Id: Id2b3c2c6d80b30552fd94face69b32223f455c68
Reviewed-on: https://chromium-review.googlesource.com/c/1296543
Commit-Queue: Mohamed Amir Yosef <mamir@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Peter Conn <peconn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610180}

components/gcm_driver/android/java/src/org/chromium/components/gcm_driver/LazySubscriptionsManager.java

@@ -194,8 +194,6 @@ public class LazySubscriptionsManager {
      *  @return The messages stored. Returns an empty list in case of failure.
      */
     public static GCMMessage[] readMessages(String subscriptionId) {
-        // TODO(https://crbug.com/882887): Make sure to delete subscription
-        // information when the token goes.
         Context context = ContextUtils.getApplicationContext();
         SharedPreferences sharedPrefs =
                 context.getSharedPreferences(PREF_PACKAGE, Context.MODE_PRIVATE);

components/gcm_driver/instance_id/android/java/src/org/chromium/components/gcm_driver/instance_id/InstanceIDBridge.java

@@ -137,6 +137,12 @@ public class InstanceIDBridge {
             protected Boolean doBackgroundWork() {
                 try {
                     mInstanceID.deleteToken(authorizedEntity, scope);
+                    String subscriptionId = LazySubscriptionsManager.buildSubscriptionUniqueId(
+                            mSubtype, authorizedEntity);
+                    if (LazySubscriptionsManager.isSubscriptionLazy(subscriptionId)) {
+                        LazySubscriptionsManager.deletePersistedMessagesForSubscriptionId(
+                                subscriptionId);
+                    }
                     return true;
                 } catch (IOException ex) {
                     return false;