From abe7d7fedba772c575b53912a2f2cf58773198f9 Mon Sep 17 00:00:00 2001
From: Erik Arvidsson <arv@chromium.org>
Date: Wed, 13 Nov 2013 14:15:50 -0500
Subject: [PATCH] Remove support for mutation events

---
 src/ShadowRenderer.js               |  7 +---
 src/wrappers/HTMLTemplateElement.js |  4 ---
 src/wrappers/events.js              | 51 +++++++++++------------------
 3 files changed, 21 insertions(+), 41 deletions(-)

diff --git a/src/ShadowRenderer.js b/src/ShadowRenderer.js
index 56afed3..c7e4a33 100644
--- a/src/ShadowRenderer.js
+++ b/src/ShadowRenderer.js
@@ -12,9 +12,7 @@
   var ShadowRoot = scope.wrappers.ShadowRoot;
   var assert = scope.assert;
   var mixin = scope.mixin;
-  var muteMutationEvents = scope.muteMutationEvents;
   var oneOf = scope.oneOf;
-  var unmuteMutationEvents = scope.unmuteMutationEvents;
   var unwrap = scope.unwrap;
   var wrap = scope.wrap;
 
@@ -358,11 +356,8 @@
         this.renderNode(shadowRoot, renderNode, node, false);
       }
 
-      if (topMostRenderer) {
-        //muteMutationEvents();
+      if (topMostRenderer)
         renderNode.sync();
-        //unmuteMutationEvents();
-      }
 
       this.dirty = false;
     },
diff --git a/src/wrappers/HTMLTemplateElement.js b/src/wrappers/HTMLTemplateElement.js
index e218aa3..c8f8867 100644
--- a/src/wrappers/HTMLTemplateElement.js
+++ b/src/wrappers/HTMLTemplateElement.js
@@ -8,10 +8,8 @@
   var HTMLElement = scope.wrappers.HTMLElement;
   var getInnerHTML = scope.getInnerHTML;
   var mixin = scope.mixin;
-  var muteMutationEvents = scope.muteMutationEvents;
   var registerWrapper = scope.registerWrapper;
   var setInnerHTML = scope.setInnerHTML;
-  var unmuteMutationEvents = scope.unmuteMutationEvents;
   var unwrap = scope.unwrap;
   var wrap = scope.wrap;
 
@@ -40,11 +38,9 @@
     var doc = getTemplateContentsOwner(templateElement.ownerDocument);
     var df = unwrap(doc.createDocumentFragment());
     var child;
-    muteMutationEvents();
     while (child = templateElement.firstChild) {
       df.appendChild(child);
     }
-    unmuteMutationEvents();
     return df;
   }
 
diff --git a/src/wrappers/events.js b/src/wrappers/events.js
index 032f6a8..6176a23 100644
--- a/src/wrappers/events.js
+++ b/src/wrappers/events.js
@@ -179,17 +179,6 @@
     return false;
   }
 
-  var mutationEventsAreSilenced = 0;
-
-  function muteMutationEvents() {
-    mutationEventsAreSilenced++;
-  }
-
-  function unmuteMutationEvents() {
-    mutationEventsAreSilenced--;
-  }
-
-  var OriginalMutationEvent = window.MutationEvent;
 
   function dispatchOriginalEvent(originalEvent) {
     // Make sure this event is only dispatched once.
@@ -197,15 +186,9 @@
       return;
     handledEventsTable.set(originalEvent, true);
 
-    // Don't do rendering if this is a mutation event since rendering might
-    // mutate the DOM which would fire more events and we would most likely
-    // just iloop.
-    if (originalEvent instanceof OriginalMutationEvent) {
-      if (mutationEventsAreSilenced)
-        return;
-    } else {
-      scope.renderAllPending();
-    }
+    // Render before dispatching the event to ensure that the event path is
+    // correct.
+    scope.renderAllPending();
 
     var target = wrap(originalEvent.target);
     var event = wrap(originalEvent);
@@ -490,13 +473,6 @@
   var MouseEvent = registerGenericEvent('MouseEvent', UIEvent, mouseEventProto);
   var FocusEvent = registerGenericEvent('FocusEvent', UIEvent, focusEventProto);
 
-  var MutationEvent = registerGenericEvent('MutationEvent', Event, {
-    initMutationEvent: getInitFunction('initMutationEvent', 3),
-    get relatedNode() {
-      return wrap(this.impl.relatedNode);
-    },
-  });
-
   // In case the browser does not support event constructors we polyfill that
   // by calling `createEvent('Foo')` and `initFooEvent` where the arguments to
   // `initFooEvent` are derived from the registered default event init dict.
@@ -569,6 +545,22 @@
     return fun && fun.handleEvent;
   }
 
+  function isMutationEvent(type) {
+    switch (type) {
+      case 'DOMAttrModified':
+      case 'DOMAttributeNameChanged':
+      case 'DOMCharacterDataModified':
+      case 'DOMElementNameChanged':
+      case 'DOMNodeInserted':
+      case 'DOMNodeInsertedIntoDocument':
+      case 'DOMNodeRemoved':
+      case 'DOMNodeRemovedFromDocument':
+      case 'DOMSubtreeModified':
+        return true;
+    }
+    return false;
+  }
+
   var OriginalEventTarget = window.EventTarget;
 
   /**
@@ -603,7 +595,7 @@
 
   EventTarget.prototype = {
     addEventListener: function(type, fun, capture) {
-      if (!isValidListener(fun))
+      if (!isValidListener(fun) || isMutationEvent(type))
         return;
 
       var listener = new Listener(type, fun, capture);
@@ -733,15 +725,12 @@
   scope.elementFromPoint = elementFromPoint;
   scope.getEventHandlerGetter = getEventHandlerGetter;
   scope.getEventHandlerSetter = getEventHandlerSetter;
-  scope.muteMutationEvents = muteMutationEvents;
-  scope.unmuteMutationEvents = unmuteMutationEvents;
   scope.wrapEventTargetMethods = wrapEventTargetMethods;
   scope.wrappers.CustomEvent = CustomEvent;
   scope.wrappers.Event = Event;
   scope.wrappers.EventTarget = EventTarget;
   scope.wrappers.FocusEvent = FocusEvent;
   scope.wrappers.MouseEvent = MouseEvent;
-  scope.wrappers.MutationEvent = MutationEvent;
   scope.wrappers.UIEvent = UIEvent;
 
 })(window.ShadowDOMPolyfill);