Mark classes with final dtors as final

- -Wfinal-dtor-non-final-class warns on classes with final dtors but
  not final classes.
- Error messages are better when the class is marked final.
- Fix existing issues in code base and a follow up will remove warning
  exemption.

Bug: 999886
Test: no errors building
Change-Id: I7ceebe66bc953a0a1211896244fe3bf9e47f1aa5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2508201
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Auto-Submit: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822680}

ui/events/gesture_detection/filtered_gesture_provider.h

@@ -18,7 +18,7 @@ namespace ui {
 
 // Provides filtered gesture detection and dispatch given a sequence of touch
 // events and touch event acks.
-class GESTURE_DETECTION_EXPORT FilteredGestureProvider
+class GESTURE_DETECTION_EXPORT FilteredGestureProvider final
     : public ui::TouchDispositionGestureFilterClient,
       public ui::GestureProviderClient {
  public: