Lock element at start of gesture sequence.

LayoutTests/fast/events/touch/gesture/gesture-tap-active-state.html

 <!DOCTYPE html>
 <html>
 <script src="../../../../resources/js-test.js"></script>
 <style type="text/css">
 #box {
     background-color: blue;
     width: 300px;
     height: 100px;
 }
 
@@ skipping 42 matching lines @@
     }
 
     if (window.testRunner) {
         window.jsTestIsAsync = true;
         testRunner.waitUntilDone();
     }
 
     debug("Verify active isn't initially set");
     shouldBeFalse("isBoxActive()");
 
+
+    debug("Verify element locked for gesture sequence");
+    debug("Box shouldn't be active after tapdown on it");
+    eventSender.gestureTapDown(50, 50);
+    shouldBeFalse("isBoxActive()");
+    debug("Box should be active after showpress outside it");
+    eventSender.gestureShowPress(400, 50);
+    shouldBeTrue("isBoxActive()");
+
     debug("Verify tapdown,tap sets and clears active");
     eventSender.gestureShowPress(50, 50);
     shouldBeTrue("isBoxActive()");
     eventSender.gestureTap(50, 50);
     // FIXME: Enable after implementing mocked timers (http://crbug.com/319529)
     // shouldBeTrue("isBoxActive()");
     waitUntilActiveCleared();
 }
 
 function waitUntilActiveCleared()
@@ skipping 49 matching lines @@
     eventSender.touchEnd();
     shouldBeTrue("isBoxActive()");
 
     finishJSTest();
 }
 
 runTests();
 </script>
 </body>
 </html>