update customElementsTakeRecords

Revert "Revert "update platform.js to get memory leak fixes""

R=jmesserly@google.com

Review URL: https://codereview.chromium.org//617413002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@40854 260f80e4-7a28-3924-810f-c04153c831b5

pkg/web_components/CHANGELOG.md

@@ -1,3 +1,14 @@
+#### Pub version 0.8.0
+  * Re-apply changes from 0.7.1+1 and also cherry pick 
+    [efdbbc](https://github.com/polymer/CustomElements/commit/efdbbc) to fix
+    the customElementsTakeRecords function.
+  * **Breaking Change** The customElementsTakeRecords function now has an
+    an optional argument `node`. There is no longer a single global observer,
+    but one for each ShadowRoot and one for the main document. The observer that
+    is actually used defaults to the main document, but if `node` is supplied
+    then it will walk up the document tree and use the first observer that it
+    finds.
+
 #### Pub version 0.7.1+2
   * Revert the change from 0.7.1+1 due to redness in FF/Safari/IE.
 

pkg/web_components/lib/build.log

@@ -1,28 +1,28 @@
 BUILD LOG
 ---------
-Build Time: 2014-09-22T10:39:00
+Build Time: 2014-10-01T13:14:41
 
 NODEJS INFORMATION
 ==================
 nodejs: v0.10.29
 chai: 1.9.1
 grunt: 0.4.5
-grunt-concat-sourcemap: 0.4.3
 grunt-audit: 0.0.3
+grunt-concat-sourcemap: 0.4.3
 grunt-contrib-concat: 0.4.0
 grunt-contrib-uglify: 0.5.1
 grunt-karma: 0.8.3
-karma: 0.12.22
-karma-crbot-reporter: 0.0.4
 karma-firefox-launcher: 0.1.3
 karma-ie-launcher: 0.1.5
-karma-mocha: 0.1.9
 karma-safari-launcher: 0.1.1
 mocha: 1.21.4
+karma-crbot-reporter: 0.0.4
+karma: 0.12.22
+karma-mocha: 0.1.9
 
 REPO REVISIONS
 ==============
-CustomElements: 85981b0986799744f452bd71ee6170f9d05851ac
+CustomElements: a9abaa0c9fd8c8faa86b77f1f7353dd91c164df0
 HTMLImports: 77efd89e04ae63a3ee7c88cb7e1d2784cf60dcb1
 ShadowDOM: bb82f0b0d361e90ca5efb1c59dd44c976ffeffb4
 URL: 35e0e6aaab5979d277afa4822a2776a7fb7562ba
@@ -30,4 +30,4 @@ platform-dev: d214582dd9537aa4cf0d6034d33c071be2970a66
 
 BUILD HASHES
 ============
-build/platform.js: fe9dc71d22c46bb23f01014e77cdda430227b114
+build/platform.js: 52a8bcc635d3db0f494ae6ad4c8303c99a045855

pkg/web_components/lib/platform.concat.js

@@ -2317,7 +2317,13 @@ window.ShadowDOMPolyfill = {};
   var globalMutationObservers = [];
   var isScheduled = false;
 
-  function scheduleCallback() {
+  function scheduleCallback(observer) {
+    if (observer.scheduled_)
+      return;
+
+    observer.scheduled_ = true;
+    globalMutationObservers.push(observer);
+
     if (isScheduled)
       return;
     setEndOfMicrotask(notifyObservers);
@@ -2337,6 +2343,7 @@ window.ShadowDOMPolyfill = {};
 
       for (var i = 0; i < notifyList.length; i++) {
         var mo = notifyList[i];
+        mo.scheduled_ = false;
         var queue = mo.takeRecords();
         removeTransientObserversFor(mo);
         if (queue.length) {
@@ -2452,8 +2459,6 @@ window.ShadowDOMPolyfill = {};
       }
     }
 
-    var anyObserversEnqueued = false;
-
     // 4.
     for (var uid in interestedObservers) {
       var observer = interestedObservers[uid];
@@ -2486,15 +2491,9 @@ window.ShadowDOMPolyfill = {};
         record.oldValue = associatedStrings[uid];
 
       // 8.
-      if (!observer.records_.length) {
-        globalMutationObservers.push(observer);
-        anyObserversEnqueued = true;
-      }
+      scheduleCallback(observer);
       observer.records_.push(record);
     }
-
-    if (anyObserversEnqueued)
-      scheduleCallback();
   }
 
   var slice = Array.prototype.slice;
@@ -2557,6 +2556,7 @@ window.ShadowDOMPolyfill = {};
     this.nodes_ = [];
     this.records_ = [];
     this.uid_ = ++uidCounter;
+    this.scheduled_ = false;
   }
 
   MutationObserver.prototype = {
@@ -2642,6 +2642,10 @@ window.ShadowDOMPolyfill = {};
       if (node === this.target)
         return;
 
+      // Make sure we remove transient observers at the end of microtask, even
+      // if we didn't get any change records.
+      scheduleCallback(this.observer);
+
       this.transientObservedNodes.push(node);
       var registrations = registrationsTable.get(node);
       if (!registrations)
@@ -11373,10 +11377,7 @@ function watchShadow(node) {
 }
 
 function watchRoot(root) {
-  if (!root.__watched) {
-    observe(root);
-    root.__watched = true;
-  }
+  observe(root);
 }
 
 function handler(mutations) {
@@ -11421,18 +11422,32 @@ function handler(mutations) {
   logFlags.dom && console.groupEnd();
 };
 
-var observer = new MutationObserver(handler);
+function takeRecords(node) {
+  // If the optional node is not supplied, assume we mean the whole document.
+  if (!node) node = wrapIfNeeded(document);
 
-function takeRecords() {
-  // TODO(sjmiles): ask Raf why we have to call handler ourselves
-  handler(observer.takeRecords());
-  takeMutations();
+  // Find the root of the tree, which will be an Document or ShadowRoot.
+  while (node.parentNode) {
+    node = node.parentNode;
+  }
+
+  var observer = node.__observer;
+  if (observer) {
+    handler(observer.takeRecords());
+    takeMutations();
+  }
 }
 
 var forEach = Array.prototype.forEach.call.bind(Array.prototype.forEach);
 
 function observe(inRoot) {
+  if (inRoot.__observer) return;
+
+  // For each ShadowRoot, we create a new MutationObserver, so the root can be
+  // garbage collected once all references to the `inRoot` node are gone.
+  var observer = new MutationObserver(handler);
   observer.observe(inRoot, {childList: true, subtree: true});
+  inRoot.__observer = observer;
 }
 
 function observeDocument(doc) {

pkg/web_components/lib/polyfill.dart

@@ -54,9 +54,8 @@ bool get _isReady {
  * This method can be used to resolve differences in timing between native and
  * polyfilled custom elements.
  */
-void customElementsTakeRecords() {
+void customElementsTakeRecords([Node node]) {
   var customElements = js.context['CustomElements'];
-  if (customElements != null) {
-    customElements.callMethod('takeRecords');
-  }
+  if (customElements == null) return;
+  customElements.callMethod('takeRecords', [node]);
 }

pkg/web_components/pubspec.yaml

@@ -1,5 +1,5 @@
 name: web_components
-version: 0.7.1+2
+version: 0.8.0
 author: Polymer.dart Authors <web-ui-dev@dartlang.org>
 homepage: https://www.dartlang.org/polymer-dart/
 description: >