[API] Fix explicit implementation assignments

platform/framework/src/load/Extension.js

@@ -134,8 +134,28 @@ define(
          */
         Extension.prototype.getImplementationPath = function () {
             return this.definition.implementation ?
-                this.bundle.getSourcePath(this.definition.implementation) :
-                undefined;
+                    this.bundle.getSourcePath(this.definition.implementation) :
+                    undefined;
+        };
+
+        /**
+         * Check if an extension has an actual implementation value
+         * (and not just a path to an implementation) defined.
+         * @returns {function} the constructor for this extension instance
+         */
+        Extension.prototype.getImplementationValue = function () {
+            return typeof this.definition.implementation === 'function' ?
+                    this.definition.implementation :
+                    undefined;
+        };
+
+        /**
+         * Check if an extension has an actual implementation value
+         * (and not just a path to an implementation) defined.
+         * @returns {boolean} true if a value is available
+         */
+        Extension.prototype.hasImplementationValue = function () {
+            return typeof this.definition.implementation === 'function';
         };
 
         /**

platform/framework/src/resolve/ExtensionResolver.js

@@ -61,10 +61,10 @@ define(
                 $log = this.$log;
 
             function loadImplementation(extension) {
-                var implValue = extension.getImplementationPath(),
-                    implPromise = (typeof implValue === 'string') ?
-                            loader.load(implValue) :
-                            Promise.resolve(implValue),
+                var implPath = extension.getImplementationPath(),
+                    implPromise = extension.hasImplementationValue() ?
+                            Promise.resolve(extension.getImplementationValue()) :
+                            loader.load(implPath),
                     definition = extension.getDefinition();
 
                 // Wrap a constructor function (to avoid modifying the original)
@@ -122,7 +122,7 @@ define(
                 // Log that loading has begun
                 $log.info([
                     "Loading implementation ",
-                    implValue,
+                    implPath,
                     " for extension ",
                     extension.getLogName()
                 ].join(""));