From a8155ea5720ddae477497acf6dc8d9ae773d6129 Mon Sep 17 00:00:00 2001
From: Mark Hammond <mhammond@skippinet.com.au>
Date: Thu, 8 Jan 2015 15:47:51 +1100
Subject: [PATCH] Bug 1119078 - only pre-fetch the sync migration sentinel if
 using a legacy identity. r=rnewman

---
 services/sync/modules/browserid_identity.js | 10 ++++++++++
 services/sync/modules/identity.js           | 16 ++++++++++++++++
 services/sync/modules/service.js            |  8 ++++----
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/services/sync/modules/browserid_identity.js b/services/sync/modules/browserid_identity.js
index 8262e0b645a..e5eaa38877f 100644
--- a/services/sync/modules/browserid_identity.js
+++ b/services/sync/modules/browserid_identity.js
@@ -399,6 +399,16 @@ this.BrowserIDManager.prototype = {
     this._shouldHaveSyncKeyBundle = false;
   },
 
+  /**
+   * Pre-fetches any information that might help with migration away from this
+   * identity.  Called after every sync and is really just an optimization that
+   * allows us to avoid a network request for when we actually need the
+   * migration info.
+   */
+  prefetchMigrationSentinel: function(service) {
+    // nothing to do here until we decide to migrate away from FxA.
+  },
+
   /**
     * Return credentials hosts for this identity only.
     */
diff --git a/services/sync/modules/identity.js b/services/sync/modules/identity.js
index 22fadb02785..2bee13b5b81 100644
--- a/services/sync/modules/identity.js
+++ b/services/sync/modules/identity.js
@@ -446,6 +446,22 @@ IdentityManager.prototype = {
     return this.username && this.basicPassword && true;
   },
 
+  /**
+   * Pre-fetches any information that might help with migration away from this
+   * identity.  Called after every sync and is really just an optimization that
+   * allows us to avoid a network request for when we actually need the
+   * migration info.
+   */
+  prefetchMigrationSentinel: function(service) {
+    // Try and fetch the migration sentinel - it will end up in the recordManager
+    // cache.
+    try {
+      service.recordManager.get(service.storageURL + "meta/fxa_credentials");
+    } catch (ex) {
+      this._log.warn("Failed to pre-fetch the migration sentinel", ex);
+    }
+  },
+
   /**
    * Obtains the array of basic logins from nsiPasswordManager.
    */
diff --git a/services/sync/modules/service.js b/services/sync/modules/service.js
index fa3e659d526..88b68505f7d 100644
--- a/services/sync/modules/service.js
+++ b/services/sync/modules/service.js
@@ -1281,12 +1281,12 @@ Sync11Service.prototype = {
       histogram.add(1);
 
       // We successfully synchronized.
-      // Try and fetch the migration sentinel - it will end up in the recordManager
-      // cache, so a sync migration doesn't need a server round-trip.
+      // Check if the identity wants to pre-fetch a migration sentinel from
+      // the server.
       // If we have no clusterURL, we are probably doing a node reassignment
-      // do don't attempt to get the credentials.
+      // so don't attempt to get it in that case.
       if (this.clusterURL) {
-        this.recordManager.get(this.storageURL + "meta/fxa_credentials");
+        this.identity.prefetchMigrationSentinel(this);
       }
 
       // Now let's update our declined engines.