Added test for useGlobePicking flag.

Specs/Scene/SceneSpec.js

@@ -593,6 +593,41 @@ defineSuite([
         expect(position).toBeDefined();
     });
 
+    it('pickPosition returns undefined when useDepthPicking is false', function() {
+        if (!scene.pickPositionSupported) {
+            return;
+        }
+
+        var rectangle = Rectangle.fromDegrees(-100.0, 30.0, -90.0, 40.0);
+        scene.camera.viewRectangle(rectangle);
+
+        var canvas = scene.canvas;
+        var windowPosition = new Cartesian2(canvas.clientWidth / 2, canvas.clientHeight / 2);
+
+        var rectanglePrimitive = new RectanglePrimitive({
+            rectangle : rectangle,
+            asynchronous : false
+        });
+        rectanglePrimitive.material.uniforms.color = new Color(1.0, 0.0, 0.0, 1.0);
+
+        var primitives = scene.primitives;
+        primitives.add(rectanglePrimitive);
+
+        scene.useDepthPicking = false;
+
+        scene.renderForSpecs();
+
+        var position = scene.pickPosition(windowPosition);
+        expect(position).not.toBeDefined();
+
+        scene.useDepthPicking = true;
+
+        scene.renderForSpecs();
+
+        position = scene.pickPosition(windowPosition);
+        expect(position).toBeDefined();
+    });
+
     it('pickPosition throws without windowPosition', function() {
         expect(function() {
             scene.pickPosition();