From a2f9c1d3fff343d4722b9e0d248dfa75a35c2448 Mon Sep 17 00:00:00 2001
From: "Kevin (Kun) \"Kassimo\" Qian" <kevinkassimo@gmail.com>
Date: Fri, 24 Aug 2018 12:24:59 -0700
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B=20Fix=20`scrollTo`=20with=20layers?=
 =?UTF-8?q?=20(#17563)?=
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* Fix scrollTo with layers

* Add Math.max
---
 src/service/viewport/viewport-impl.js | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/src/service/viewport/viewport-impl.js b/src/service/viewport/viewport-impl.js
index c5cf851d6d3a..a1f16e7594cd 100644
--- a/src/service/viewport/viewport-impl.js
+++ b/src/service/viewport/viewport-impl.js
@@ -555,19 +555,15 @@ export class Viewport {
         offset = 0;
         break;
     }
-    let newScrollTop;
-    let curScrollTopPromise;
 
-    if (this.useLayers_) {
-      newScrollTop = elementRect.top + offset;
-      curScrollTopPromise = Promise.resolve(0);
-    } else {
-      const calculatedScrollTop = elementRect.top - this.paddingTop_ + offset;
-      newScrollTop = Math.max(0, calculatedScrollTop);
-      curScrollTopPromise = this.getElementScrollTop_(parent);
-    }
-
-    return curScrollTopPromise.then(curScrollTop => {
+    return this.getElementScrollTop_(parent).then(curScrollTop => {
+      let newScrollTop;
+      if (this.useLayers_) {
+        newScrollTop = Math.max(0, elementRect.top + offset + curScrollTop);
+      } else {
+        const calculatedScrollTop = elementRect.top - this.paddingTop_ + offset;
+        newScrollTop = Math.max(0, calculatedScrollTop);
+      }
       if (newScrollTop == curScrollTop) {
         return;
       }