From 84fa3bf38333f07bb1f189e981635463e0eb598f Mon Sep 17 00:00:00 2001
From: Daniel Freedman <dfreedm@google.com>
Date: Wed, 29 Nov 2017 12:17:00 -0800
Subject: [PATCH] Do not set touchend listeners to passive

`touchend` listeners do not need to be passive to enable more performant
scrolling.

With this change, most of the tradeoffs with enabling
`passiveTouchGestures` disappear, leaving only the inability to control
scrolling from `track`, `down`, and `move` gestures.

Fixes #4961
---
 lib/utils/gestures.html          |  4 ++--
 test/smoke/passive-gestures.html | 10 ++++++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/utils/gestures.html b/lib/utils/gestures.html
index b741455a9d..be74db8e90 100644
--- a/lib/utils/gestures.html
+++ b/lib/utils/gestures.html
@@ -481,7 +481,7 @@
           gobj[dep] = gd = {_count: 0};
         }
         if (gd._count === 0) {
-          let options = !isMouseEvent(dep) && PASSIVE_TOUCH();
+          let options = !isMouseEvent(dep) && dep !== 'touchend' && PASSIVE_TOUCH();
           node.addEventListener(dep, this._handleNative, options);
         }
         gd[name] = (gd[name] || 0) + 1;
@@ -515,7 +515,7 @@
             gd[name] = (gd[name] || 1) - 1;
             gd._count = (gd._count || 1) - 1;
             if (gd._count === 0) {
-              let options = !isMouseEvent(dep) && PASSIVE_TOUCH();
+              let options = !isMouseEvent(dep) && dep !== 'touchend' && PASSIVE_TOUCH();
               node.removeEventListener(dep, this._handleNative, options);
             }
           }
diff --git a/test/smoke/passive-gestures.html b/test/smoke/passive-gestures.html
index 90e7a9363c..cc578a2d52 100644
--- a/test/smoke/passive-gestures.html
+++ b/test/smoke/passive-gestures.html
@@ -40,11 +40,17 @@
       is: 'x-passive',
       listeners: {
         'down': 'prevent',
-        'move': 'prevent'
+        'move': 'prevent',
+        'up': 'prevent',
+        'tap': 'allowed',
+        'click': 'allowed'
       },
       prevent(e) {
         e.preventDefault();
-        console.log('prevented!');
+        console.log('prevented?: ' + e.type + ' ' + e.defaultPrevented);
+      },
+      allowed(e) {
+        console.log(e.type + ' allowed');
       }
     });
   </script>