Pass a WeakPersistent ScrollableArea object to a ScrollCallback

Make ScrollableArea WeakPersistent so we do not need to worry about
when we call "area->MarkHoverStateDirty()", ScrollableArea object
"area" has been destructed.

Bug: 978830
Change-Id: I0e0c11987e4d87e1c8718dbe582354d349771c2b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1678257Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: Lan Wei <lanwei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672584}

third_party/blink/renderer/core/input/scroll_manager.cc

@@ -324,7 +324,7 @@ bool ScrollManager::LogicalScroll(ScrollDirection direction,
             if (area)
               area->MarkHoverStateDirty();
           },
-          scrollable_area));
+          WrapWeakPersistent(scrollable_area)));
     }
     ScrollResult result = scrollable_area->UserScroll(
         granularity, ToScrollDelta(physical_direction, 1), std::move(callback));