From bada2909049680c3efa9a74d51641c03bcc00a43 Mon Sep 17 00:00:00 2001
From: Collin Jackson <jackson@google.com>
Date: Wed, 27 Jan 2016 16:14:38 -0800
Subject: [PATCH] =?UTF-8?q?Mark=20Firebase=E2=80=99s=20previousChildName?=
 =?UTF-8?q?=20as=20optional=20since=20it=20will=20be=20null=20for=20the=20?=
 =?UTF-8?q?first=20item?=
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Content-Type: text/plain; charset=UTF-8
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---
 sky/services/firebase/firebase.mojom | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sky/services/firebase/firebase.mojom b/sky/services/firebase/firebase.mojom
index b7c8f26ab41..4b2beda5b07 100644
--- a/sky/services/firebase/firebase.mojom
+++ b/sky/services/firebase/firebase.mojom
@@ -36,9 +36,9 @@ interface ValueEventListener {
 
 interface ChildEventListener {
   OnCancelled(Error error);
-  OnChildAdded(DataSnapshot snapshot, string previousChildName);
-  OnChildChanged(DataSnapshot snapshot, string previousChildName);
-  OnChildMoved(DataSnapshot snapshot, string previousChildName);
+  OnChildAdded(DataSnapshot snapshot, string? previousChildName);
+  OnChildChanged(DataSnapshot snapshot, string? previousChildName);
+  OnChildMoved(DataSnapshot snapshot, string? previousChildName);
   OnChildRemoved(DataSnapshot snapshot);
 };