Fixes #2039: Polymer.dom.flush now triggers Custom Elements polyfill …

…mutations and includes an api (`Polymer.dom.addDebouncer(debouncer)`) for adding debouncers which should run at flush time. Template rendering debouncers are placed in the flush list.

@@ -24,8 +24,6 @@
     var nativeCloneNode = Element.prototype.cloneNode;
     var nativeImportNode = Document.prototype.importNode;
 
-    var dirtyRoots = [];
-
     var DomApi = function(node) {
       this.node = node;
       if (this.patch) {
@@ -36,11 +34,7 @@
     DomApi.prototype = {
 
       flush: function() {
-        for (var i=0, host; i<dirtyRoots.length; i++) {
-          host = dirtyRoots[i];
-          host.flushDebouncer('_distribute');
-        }
-        dirtyRoots = [];
+        flush();
       },
 
       _lazyDistribute: function(host) {
@@ -48,8 +42,7 @@
         // we don't distribute before initial distribution
         if (host.shadyRoot && host.shadyRoot._distributionClean) {
           host.shadyRoot._distributionClean = false;
-          host.debounce('_distribute', host._distributeContent);
-          dirtyRoots.push(host);
+          addDebouncer(host.debounce('_distribute', host._distributeContent));
         }
       },
 
@@ -773,8 +766,54 @@
       }
     };
 
-    // make flush available directly.
-    Polymer.dom.flush = DomApi.prototype.flush;
+    // flush and debounce exposed as statics on Polymer.dom
+    var flush = Polymer.dom.flush = function() {
+      // first make any pending CE mutations that might trigger debouncer
+      // additions go...
+      flush.flushPolyfills();
+      // flush debouncers
+      for (var i=0; i < flush._debouncers.length; i++) {
+        flush._debouncers[i].complete();
+      }
+      // clear the list of debouncers
+      if (flush._finishDebouncer) {
+        flush._finishDebouncer.complete();
+      }
+      // again make any pending CE mutations that might trigger debouncer
+      // additions go...
+      flush.flushPolyfills();
+      // flush again if there are now any debouncers to process
+      if (flush._debouncers.length && flush.guard < flush.MAX) {
+        flush.guard++;
+        flush();
+      } else {
+        flush.guard = 0;
+      }
+    };
+
+    flush.guard = 0;
+    flush.MAX = 10;
+    flush._needsTakeRecords = !Polymer.Settings.useNativeCustomElements;
+    // TODO(sorvell): There is currently not a good way 
+    // to process all custom elements mutations under SD polyfill because
+    // these mutations may be inside shadowRoots. 
+    flush.flushPolyfills = function() {
+      if (this._needsTakeRecords) {
+        CustomElements.takeRecords();
+      }
+    }
+    flush._debouncers = [];
+    flush._finishDebouncer;
+    
+    var addDebouncer = Polymer.dom.addDebouncer = function(debouncer) {
+      flush._debouncers.push(debouncer);
+      // ensure the list of active debouncers is cleared when done.
+      flush._finishDebouncer = Polymer.Debounce(flush._finishDebouncer, 
+        function() {
+          flush._debouncers = [];
+        }
+      );
+    };
 
     function getLightChildren(node) {
       var children = node._lightChildren;

@@ -70,20 +70,10 @@
       }
     },
 
-    // Intentionally static object
-    _templatizerStatic: {
-      count: 0,
-      callbacks: {},
-      debouncer: null
-    },
-
     // Extension point for overrides
     _instanceProps: Polymer.nob,
 
-    created: function() {
-      // id used for consolidated debouncer
-      this._templatizerId = this._templatizerStatic.count++;
-    },
+    _parentPropPrefix: '_parent_',
 
     /**
      * Prepares a template containing Polymer bindings by generating
@@ -162,24 +152,11 @@
     },
 
     _debounceTemplate: function(fn) {
-      this._templatizerStatic.callbacks[this._templatizerId] = fn.bind(this);
-      this._templatizerStatic.debouncer =
-        Polymer.Debounce(this._templatizerStatic.debouncer,
-          this._flushTemplates.bind(this, true));
+      Polymer.dom.addDebouncer(this.debounce('_debounceTemplate', fn));
     },
 
     _flushTemplates: function(debouncerExpired) {
-      var db = this._templatizerStatic.debouncer;
-      // completely flush any re-queued callbacks resulting from stamping
-      while (debouncerExpired || (db && db.finish)) {
-        db.stop();
-        var cbs = this._templatizerStatic.callbacks;
-        this._templatizerStatic.callbacks = {};
-        for (var id in cbs) {
-          cbs[id]();
-        }
-        debouncerExpired = false;
-      }
+      Polymer.dom.flush();
     },
 
     _customPrepEffects: function(archetype) {
@@ -236,7 +213,7 @@
           // to template instances through abstract _forwardParentProp API
           // that should be implemented by Templatizer users
           for (prop in parentProps) {
-            var parentProp = '_parent_' + prop;
+            var parentProp = this._parentPropPrefix + prop;
             var effects = [{
               kind: 'function',
               effect: this._createForwardPropEffector(prop)
@@ -263,8 +240,9 @@
     },
 
     _createHostPropEffector: function(prop) {
+      var prefix = this._parentPropPrefix;
       return function(source, value) {
-        this.dataHost['_parent_' + prop] = value;
+        this.dataHost[prefix + prop] = value;
       };
     },
 
@@ -304,14 +282,14 @@
       // Call extension point for Templatizer sub-classes
       dataHost._forwardInstancePath.call(dataHost, this, path, value);
       if (root in dataHost._parentProps) {
-        dataHost.notifyPath('_parent_' + path, value);
+        dataHost.notifyPath(dataHost._parentPropPrefix + path, value);
       }
     },
 
     // Overrides Base notify-path module
     _pathEffector: function(path, value, fromAbove) {
       if (this._forwardParentPath) {
-        if (path.indexOf('_parent_') === 0) {
+        if (path.indexOf(this._parentPropPrefix) === 0) {
           this._forwardParentPath(path.substring(8), value);
         }
       }
@@ -319,7 +297,7 @@
     },
 
     _constructorImpl: function(model, host) {
-      this._rootDataHost = host._getRootDataHost();
+      this._rootDataHost = host._getRootDataHost() || host;
       this._setupConfigure(model);
       this._pushHost(host);
       this.root = this.instanceTemplate(this._template);
@@ -391,7 +369,7 @@
       model = model || {};
       if (this._parentProps) {
         for (var prop in this._parentProps) {
-          model[prop] = this['_parent_' + prop];
+          model[prop] = this[this._parentPropPrefix + prop];
         }
       }
       return new this.ctor(model, this);