tracking: rework tracking API

- simplify Tracker API
- fix perf tests (don't measure video decoding)

modules/tracking/misc/java/test/TrackerCreateTest.java

@@ -0,0 +1,38 @@
+package org.opencv.test.tracking;
+
+import org.opencv.core.Core;
+import org.opencv.core.CvException;
+import org.opencv.test.OpenCVTestCase;
+
+import org.opencv.tracking.Tracking;
+import org.opencv.tracking.Tracker;
+import org.opencv.tracking.TrackerGOTURN;
+import org.opencv.tracking.TrackerKCF;
+import org.opencv.tracking.TrackerMIL;
+
+public class TrackerCreateTest extends OpenCVTestCase {
+
+    @Override
+    protected void setUp() throws Exception {
+        super.setUp();
+    }
+
+
+    public void testCreateTrackerGOTURN() {
+        try {
+            Tracker tracker = TrackerGOTURN.create();
+            assert(tracker != null);
+        } catch (CvException e) {
+            // expected, model files may be missing
+        }
+    }
+
+    public void testCreateTrackerKCF() {
+        Tracker tracker = TrackerKCF.create();
+    }
+
+    public void testCreateTrackerMIL() {
+        Tracker tracker = TrackerMIL.create();
+    }
+
+}