Implement elementFromPoint for document and ShadowRoot

src/wrappers/Document.js

@@ -6,17 +6,18 @@
   'use strict';
 
   var GetElementsByInterface = scope.GetElementsByInterface;
+  var Node = scope.wrappers.Node;
   var ParentNodeInterface = scope.ParentNodeInterface;
   var SelectorsInterface = scope.SelectorsInterface;
-  var Node = scope.wrappers.Node;
   var defineWrapGetter = scope.defineWrapGetter;
+  var elementFromPoint = scope.elementFromPoint;
+  var forwardMethodsToWrapper = scope.forwardMethodsToWrapper;
   var mixin = scope.mixin;
   var registerWrapper = scope.registerWrapper;
   var unwrap = scope.unwrap;
   var wrap = scope.wrap;
   var wrapEventTargetMethods = scope.wrapEventTargetMethods;
   var wrapNodeList = scope.wrapNodeList;
-  var forwardMethodsToWrapper = scope.forwardMethodsToWrapper;
 
   var implementationTable = new SideTable();
 
@@ -55,10 +56,16 @@
   ].forEach(wrapMethod);
 
   var originalAdoptNode = document.adoptNode;
-  Document.prototype.adoptNode = function(node) {
-    originalAdoptNode.call(this.impl, unwrap(node));
-    return node;
-  };
+
+  mixin(Document.prototype, {
+    adoptNode: function(node) {
+      originalAdoptNode.call(this.impl, unwrap(node));
+      return node;
+    },
+    elementFromPoint: function(x, y) {
+      return elementFromPoint(this, this, x, y);
+    }
+  });
 
   // We also override some of the methods on document.body and document.head
   // for convenience.
@@ -88,6 +95,7 @@
     'createEvent',
     'createEventNS',
     'createTextNode',
+    'elementFromPoint',
     'getElementById',
   ]);
 

src/wrappers/EventTarget.js

@@ -580,7 +580,24 @@
     forwardMethodsToWrapper(constructors, methodNames);
   }
 
+
+  var originalElementFromPoint = document.elementFromPoint;
+
+  function elementFromPoint(self, document, x, y) {
+    scope.renderAllPending();
+
+    var element = wrap(originalElementFromPoint.call(document.impl, x, y));
+    var targets = retarget(element, this)
+    for (var i = 0; i < targets.length; i++) {
+      var target = targets[i];
+      if (target.currentTarget === self)
+        return target.target;
+    }
+    return null;
+  }
+
   scope.adjustRelatedTarget = adjustRelatedTarget;
+  scope.elementFromPoint = elementFromPoint;
   scope.wrapEventTargetMethods = wrapEventTargetMethods;
   scope.wrappers.CustomEvent = CustomEvent;
   scope.wrappers.Event = Event;

src/wrappers/ShadowRoot.js

@@ -6,6 +6,7 @@
   'use strict';
 
   var DocumentFragment = scope.wrappers.DocumentFragment;
+  var elementFromPoint = scope.elementFromPoint;
   var getInnerHTML = scope.getInnerHTML;
   var mixin = scope.mixin;
   var rewrap = scope.rewrap;
@@ -42,6 +43,10 @@
 
     invalidateShadowRenderer: function() {
       return shadowHostTable.get(this).invalidateShadowRenderer();
+    },
+
+    elementFromPoint: function(x, y) {
+      return elementFromPoint(this, this.ownerDocument, x, y);
     }
   });
 

test/Document.js

@@ -160,4 +160,32 @@ suite('Document', function() {
     assert.equal(div, div3);
     assert.equal(div.ownerDocument, doc2);
   });
+
+  test('elementFromPoint', function() {
+    div = document.body.appendChild(document.createElement('div'));
+    div.style.cssText = 'position: fixed; background: green; ' +
+                        'width: 10px; height: 10px; top: 0; left: 0;';
+
+    assert.equal(document.elementFromPoint(5, 5), div);
+
+    var doc = wrap(document);
+    assert.equal(doc.elementFromPoint(5, 5), div);
+  });
+
+  test('elementFromPoint in shadow', function() {
+    div = document.body.appendChild(document.createElement('div'));
+    div.style.cssText = 'position: fixed; background: red; ' +
+                        'width: 10px; height: 10px; top: 0; left: 0;';
+    var sr = div.createShadowRoot();
+    sr.innerHTML = '<a></a>';
+    var a = sr.firstChild;
+    a.style.cssText = 'position: absolute; width: 100%; height: 100%; ' +
+                      'background: green';
+
+    assert.equal(document.elementFromPoint(5, 5), div);
+
+    var doc = wrap(document);
+    assert.equal(doc.elementFromPoint(5, 5), div);
+  });
+
 });

test/ShadowRoot.js

@@ -0,0 +1,29 @@
+// Copyright 2013 The Toolkitchen Authors. All rights reserved.
+// Use of this source code is goverened by a BSD-style
+// license that can be found in the LICENSE file.
+
+suite('ShadowRoot', function() {
+
+  var div;
+  teardown(function() {
+    if (div) {
+      if (div.parentNode)
+        div.parentNode.removeChild(div);
+      div = undefined;
+    }
+  });
+
+  test('elementFromPoint', function() {
+    div = document.body.appendChild(document.createElement('div'));
+    div.style.cssText = 'position: fixed; background: red; ' +
+                        'width: 10px; height: 10px; top: 0; left: 0;';
+    var sr = div.createShadowRoot();
+    sr.innerHTML = '<a></a>';
+    var a = sr.firstChild;
+    a.style.cssText = 'position: absolute; width: 100%; height: 100%; ' +
+                      'background: green';
+
+    assert.equal(sr.elementFromPoint(5, 5), a);
+  });
+
+});

test/test.main.js

@@ -80,6 +80,7 @@ var modules = [
   'HTMLTemplateElement.js',
   'MutationObserver.js',
   'ParentNodeInterface.js',
+  'ShadowRoot.js',
   'Text.js',
   'Window.js',
   'custom-element.js',