From e96e674201c7dfccf7f39f8b22711f3a803de7e9 Mon Sep 17 00:00:00 2001
From: Ben Gotow <bengotow@gmail.com>
Date: Thu, 21 Jan 2016 16:31:31 -0800
Subject: [PATCH] Properly clean up NSEvent monitor

---
 atom/browser/native_window_mac.h  |  1 +
 atom/browser/native_window_mac.mm | 33 +++++++++++++++++--------------
 2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/atom/browser/native_window_mac.h b/atom/browser/native_window_mac.h
index ef3ccb1502..927e971d9b 100644
--- a/atom/browser/native_window_mac.h
+++ b/atom/browser/native_window_mac.h
@@ -110,6 +110,7 @@ class NativeWindowMac : public NativeWindow {
 
   base::scoped_nsobject<AtomNSWindow> window_;
   base::scoped_nsobject<AtomNSWindowDelegate> window_delegate_;
+  base::scoped_nsobject<id> event_monitor_;
 
   // The view that will fill the whole frameless window.
   base::scoped_nsobject<FullSizeContentView> content_view_;
diff --git a/atom/browser/native_window_mac.mm b/atom/browser/native_window_mac.mm
index 198a78e3f5..88476eafbf 100644
--- a/atom/browser/native_window_mac.mm
+++ b/atom/browser/native_window_mac.mm
@@ -491,28 +491,31 @@ NativeWindowMac::NativeWindowMac(
   [view setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
 
   BOOL __block down = NO;
-  [NSEvent addLocalMonitorForEventsMatchingMask:NSScrollWheelMask handler:^NSEvent * _Nullable(NSEvent * event) {
-    if (![window_ isKeyWindow])
-      return event;
+  event_monitor_.reset([[NSEvent
+    addLocalMonitorForEventsMatchingMask:NSScrollWheelMask
+    handler:^NSEvent * _Nullable(NSEvent * event) {
+      if (![window_ isKeyWindow])
+        return event;
 
-    if (!web_contents)
-      return event;
+      if (!web_contents)
+        return event;
 
-    if (!down && (([event phase] == NSEventPhaseMayBegin) || ([event phase] == NSEventPhaseBegan))) {
-      this->NotifyWindowScrollTouchDown();
-      down = YES;
-    }
-    if (down && (([event phase] == NSEventPhaseEnded) || ([event phase] == NSEventPhaseCancelled))) {
-      this->NotifyWindowScrollTouchUp();
-      down = NO;
-    }
-    return event;
-  }];
+      if (!down && (([event phase] == NSEventPhaseMayBegin) || ([event phase] == NSEventPhaseBegan))) {
+        this->NotifyWindowScrollTouchBegin();
+        down = YES;
+      }
+      if (down && (([event phase] == NSEventPhaseEnded) || ([event phase] == NSEventPhaseCancelled))) {
+        this->NotifyWindowScrollTouchEnd();
+        down = NO;
+      }
+      return event;
+  }] retain]);
 
   InstallView();
 }
 
 NativeWindowMac::~NativeWindowMac() {
+  [NSEvent removeMonitor: event_monitor_.get()];
   Observe(nullptr);
 }