From 9530ccd561dd75f274d75b51740999d9bc1c524c Mon Sep 17 00:00:00 2001
From: Olli Pettay <Olli.Pettay@helsinki.fi>
Date: Mon, 5 Sep 2016 19:34:30 +0300
Subject: [PATCH] Bug 1298504, ensure existing listeners are correctly counted
 before disabling some device APIs, r=mccr8

---
 dom/events/EventListenerManager.cpp | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/dom/events/EventListenerManager.cpp b/dom/events/EventListenerManager.cpp
index fa235d8e6b26..bf3916760696 100644
--- a/dom/events/EventListenerManager.cpp
+++ b/dom/events/EventListenerManager.cpp
@@ -654,6 +654,7 @@ EventListenerManager::RemoveEventListenerInternal(
   uint32_t count = mListeners.Length();
   uint32_t typeCount = 0;
   bool deviceType = IsDeviceType(aEventMessage);
+  bool didRemove = false;
 
   RefPtr<EventListenerManager> kungFuDeathGrip(this);
 
@@ -665,18 +666,22 @@ EventListenerManager::RemoveEventListenerInternal(
       if (listener->mListener == aListenerHolder &&
           listener->mFlags.EqualsForRemoval(aFlags)) {
         mListeners.RemoveElementAt(i);
+        didRemove = true;
         --count;
-        NotifyEventListenerRemoved(aUserType);
+        --i;
         if (!deviceType) {
-          return;
+          break;
         }
         --typeCount;
       }
     }
   }
 
-  if (!aAllEvents && deviceType && typeCount == 0) {
-    DisableDevice(aEventMessage);
+  if(didRemove) {
+    NotifyEventListenerRemoved(aUserType);
+    if (!aAllEvents && deviceType && typeCount == 0) {
+      DisableDevice(aEventMessage);
+    }
   }
 }