Add the host property to the ShadowRoot interface

https://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/shadow/index.html#api-shadow-root-host

src/ShadowRenderer.js

@@ -11,7 +11,6 @@
   var Node = scope.wrappers.Node;
   var ShadowRoot = scope.wrappers.ShadowRoot;
   var assert = scope.assert;
-  var getHostForShadowRoot = scope.getHostForShadowRoot;
   var mixin = scope.mixin;
   var muteMutationEvents = scope.muteMutationEvents;
   var oneOf = scope.oneOf;
@@ -253,7 +252,7 @@
   }
 
   function getRendererForShadowRoot(shadowRoot) {
-    return getRendererForHost(getHostForShadowRoot(shadowRoot));
+    return getRendererForHost(shadowRoot.host);
   }
 
   var spliceDiff = new ArraySplice();

src/wrappers/ShadowRoot.js

@@ -43,6 +43,10 @@
       return nextOlderShadowTreeTable.get(this) || null;
     },
 
+    get host() {
+      return shadowHostTable.get(this) || null;
+    },
+
     invalidateShadowRenderer: function() {
       return shadowHostTable.get(this).invalidateShadowRenderer();
     },
@@ -57,7 +61,4 @@
   });
 
   scope.wrappers.ShadowRoot = ShadowRoot;
-  scope.getHostForShadowRoot = function(node) {
-    return shadowHostTable.get(node);
-  };
 })(this.ShadowDOMPolyfill);

src/wrappers/events.js

@@ -49,7 +49,7 @@
 
     // 1.
     if (isShadowRoot(node))
-      return getInsertionParent(node) || scope.getHostForShadowRoot(node);
+      return getInsertionParent(node) || node.host;
 
     // 2.
     var eventParents = scope.eventParentsTable.get(node);
@@ -145,7 +145,7 @@
         ancestor = calculateParents(ancestor, context, ancestors);  // 3.4.7.
       }
       if (isShadowRoot(target))  // 3.5.
-        target = scope.getHostForShadowRoot(target);
+        target = target.host;
       else
         target = target.parentNode;  // 3.6.
     }
@@ -174,10 +174,8 @@
   function enclosedBy(a, b) {
     if (a === b)
       return true;
-    if (a instanceof wrappers.ShadowRoot) {
-      var host = scope.getHostForShadowRoot(a);
-      return enclosedBy(rootOfNode(host), b);
-    }
+    if (a instanceof wrappers.ShadowRoot)
+      return enclosedBy(rootOfNode(a.host), b);
     return false;
   }
 
@@ -599,7 +597,7 @@
 
   function getTargetToListenAt(wrapper) {
     if (wrapper instanceof wrappers.ShadowRoot)
-      wrapper = scope.getHostForShadowRoot(wrapper);
+      wrapper = wrapper.host;
     return unwrap(wrapper);
   }
 

test/js/ShadowRoot.js

@@ -56,4 +56,13 @@ suite('ShadowRoot', function() {
     assert.equal(sr2.olderShadowRoot, sr);
   });
 
+  test('host', function() {
+    var host = document.createElement('div');
+    var sr = host.createShadowRoot();
+    assert.equal(host, sr.host);
+
+    var sr2 = host.createShadowRoot();
+    assert.equal(host, sr2.host);
+  });
+
 });