Make EventHandler::ActiveIntervalTimer mockable.

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

Index: LayoutTests/fast/events/touch/gesture/gesture-tap-active-state-iframe.html
diff --git a/LayoutTests/fast/events/touch/gesture/gesture-tap-active-state-iframe.html b/LayoutTests/fast/events/touch/gesture/gesture-tap-active-state-iframe.html
index db501df4a48417b22d2793096ccb9ae71c7120bd..338969792e79d0b4dbed0de9ca8e387379faf999 100644
--- a/LayoutTests/fast/events/touch/gesture/gesture-tap-active-state-iframe.html
+++ b/LayoutTests/fast/events/touch/gesture/gesture-tap-active-state-iframe.html
@@ -38,6 +38,14 @@ function runTests(ba)
         return;
     }
 
+    if (!internals.fireActiveIntervalTimer) {
+        debug('Mocked timers are not supported by this platform');
+        return;
+    }
+
+    var iframeDoc = document.getElementById('frame').contentDocument;
+    internals.suspendActiveIntervalTimer(iframeDoc);
+
     // Scroll so the box is at the top
     window.scrollTo(0, 400);
 
@@ -48,17 +56,8 @@ function runTests(ba)
     eventSender.gestureShowPress(450, 50);
     shouldBeTrue("isBoxActive()");
     eventSender.gestureTap(450, 50);
-    // FIXME: Enable after implementing mocked timers (http://crbug.com/319529)
-    // shouldBeTrue("isBoxActive()");
-    waitUntilActiveCleared();
-}
-
-function waitUntilActiveCleared()
-{
-    if(isBoxActive()) {
-        return setTimeout(waitUntilActiveCleared, 10);
-    }
-
+    shouldBeTrue("isBoxActive()");
+    internals.fireActiveIntervalTimer(iframeDoc);
     shouldBeFalse("isBoxActive()");
     finishJSTest();
 }