[Tree] Show root for most trees

Modify tree so that it includes its root in most cases, for
WTD-922.

platform/commonUI/general/bundle.json

@@ -151,6 +151,12 @@
             {
                 "key": "tree",
                 "templateUrl": "templates/tree.html",
+                "type": "root",
+                "priority": "preferred"
+            },
+            {
+                "key": "tree",
+                "templateUrl": "templates/subtree.html",
                 "uses": [ "composition" ]
             },
             {

platform/commonUI/general/res/templates/subtree.html

@@ -0,0 +1,14 @@
+<ul class="tree">
+    <li ng-if="!composition">
+        <span class="tree-item">
+            <span class="icon wait-spinner"></span>
+            <span class="title-label">Loading...</span>
+        </span>
+    </li>
+    <li ng-repeat="child in composition">
+        <mct-representation key="'tree-node'"
+                            mct-object="child"
+                            ng-model="ngModel">
+        </mct-representation>
+    </li>
+</ul>

platform/commonUI/general/res/templates/tree.html

@@ -1,13 +1,7 @@
 <ul class="tree">
-    <li ng-if="!composition">
-        <span class="tree-item">
-            <span class="icon wait-spinner"></span>
-            <span class="title-label">Loading...</span>
-        </span>
-    </li>
-    <li ng-repeat="child in composition">
+    <li>
         <mct-representation key="'tree-node'"
-                            mct-object="child"
+                            mct-object="domainObject"
                             ng-model="ngModel">
         </mct-representation>
     </li>

platform/core/src/models/RootModelProvider.js

@@ -28,6 +28,7 @@ define(
             function addRoot(models) {
                 models.ROOT = {
                     name: "The root object",
+                    type: "root",
                     composition: ids
                 };
                 return models;

platform/representation/src/MCTRepresentation.js

@@ -32,25 +32,43 @@ define(
          * @param {ViewDefinition[]} views an array of view extensions
          */
         function MCTRepresentation(representations, views, representers, $q, $log) {
-            var pathMap = {},
-                representationMap = {},
+            var representationMap = {},
                 gestureMap = {};
 
             // Assemble all representations and views
             // The distinction between views and representations is
             // not important her (view is-a representation)
             representations.concat(views).forEach(function (representation) {
-                var path = [
+                var key = representation.key;
+
+                // Store the representation
+                representationMap[key] = representationMap[key] || [];
+                representationMap[representation.key].push(representation);
+            });
+
+            // Get a path to a representation
+            function getPath(representation) {
+                return [
                     representation.bundle.path,
                     representation.bundle.resources,
                     representation.templateUrl
                 ].join("/");
+            }
 
-                // Consider allowing multiple templates with the same key
-                pathMap[representation.key] = path;
-                representationMap[representation.key] = representation;
-            });
-
+            // Look up a matching representation for this domain object
+            function lookup(key, domainObject) {
+                var candidates = representationMap[key] || [],
+                    type,
+                    i;
+                // Filter candidates by object type
+                for (i = 0; i < candidates.length; i += 1) {
+                    type = candidates[i].type;
+                    if (!type || !domainObject ||
+                            domainObject.getCapability('type').instanceOf(type)) {
+                        return candidates[i];
+                    }
+                }
+            }
 
             function link($scope, element, attrs) {
                 var activeRepresenters = representers.map(function (Representer) {
@@ -89,8 +107,8 @@ define(
                 // as appropriate for current representation key and
                 // domain object.
                 function refresh() {
-                    var representation = representationMap[$scope.key],
-                        domainObject = $scope.domainObject,
+                    var domainObject = $scope.domainObject,
+                        representation = lookup($scope.key, domainObject),
                         uses = ((representation || {}).uses || []),
                         gestureKeys = ((representation || {}).gestures || []);
 
@@ -100,7 +118,7 @@ define(
 
                     // Look up the actual template path, pass it to ng-include
                     // via the "inclusion" field
-                    $scope.inclusion = pathMap[$scope.key];
+                    $scope.inclusion = representation && getPath(representation);
 
                     // Any existing gestures are no longer valid; release them.
                     activeRepresenters.forEach(function (activeRepresenter) {