Increase reliablity of scorllingcoordinator layout tests

LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change.html

Index: LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change.html
diff --git a/LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change.html b/LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change.html
index d12c034f7dad840ff3b1396af32e96ae9f7c1f65..553a245c3147f7adca150334a6c062a24d080b7d 100644
--- a/LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change.html
+++ b/LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change.html
@@ -77,7 +77,7 @@
       // Next 3 statements have no functional impact just visual
       showSectionIf(function(){return true;});
       awaitCompsitingUpdate(function(){
-        runNonFastScrollableRegionTest();
+        drawNonFastScrollableRegionOverlays();
 
         finishJSTest();
       });
@@ -157,13 +157,4 @@
     for (var i = 0; i < sections.length; i++)
       sections[i].style.display = condition(sections[i]) ? 'block' : 'none';
   }
-
-  // Waits for one RAF call to ensure compositing update has occurred and invokes task.
-  function awaitCompsitingUpdate(task) {
-    window.requestAnimationFrame(task);
-  }
-
-  function rectToString(rect) {
-    return '[' + [rect.left, rect.top, rect.width, rect.height].join(', ') + ']';
-  }
 </script>