Matching ScrollableArea pre-finalizer scheme to new docs

Existing code executed parent pre-finalizer before subclass
pre-finalizer. Corrected the order.

Bug: 981043
Change-Id: I4b25cf8c6ee1d8145f77e5ed46e87eeae22357f7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1696964Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676352}

third_party/blink/renderer/core/frame/visual_viewport.cc

@@ -1207,7 +1207,7 @@ std::unique_ptr<TracedValue> VisualViewport::ViewportToTracedValue() const {
   return value;
 }
 
-void VisualViewport::PreFinalize() {
+void VisualViewport::DisposeImpl() {
   root_transform_layer_.reset();
   inner_viewport_container_layer_.reset();
   overscroll_elasticity_layer_.reset();
@@ -1226,6 +1226,7 @@ void VisualViewport::PreFinalize() {
   scroll_node_.reset();
   horizontal_scrollbar_effect_node_.reset();
   vertical_scrollbar_effect_node_.reset();
+  ScrollableArea::DisposeImpl();
 }
 
 }  // namespace blink

third_party/blink/renderer/core/frame/visual_viewport.h

@@ -274,7 +274,7 @@ class CORE_EXPORT VisualViewport final
   void SetNeedsPaintPropertyUpdate() { needs_paint_property_update_ = true; }
   bool NeedsPaintPropertyUpdate() const { return needs_paint_property_update_; }
 
-  void PreFinalize() override;
+  void DisposeImpl() override;
 
  private:
   bool DidSetScaleOrLocation(float scale,

third_party/blink/renderer/core/paint/paint_layer_scrollable_area.cc

@@ -2928,10 +2928,11 @@ bool PaintLayerScrollableArea::ScrollingBackgroundDisplayItemClient::
       ->PaintedOutputOfObjectHasNoEffectRegardlessOfSize();
 }
 
-void PaintLayerScrollableArea::PreFinalize() {
+void PaintLayerScrollableArea::DisposeImpl() {
   if (!HasBeenDisposed())
     Dispose();
   rare_data_.reset();
+  ScrollableArea::DisposeImpl();
 }
 
 }  // namespace blink

third_party/blink/renderer/core/paint/paint_layer_scrollable_area.h

@@ -545,7 +545,7 @@ class CORE_EXPORT PaintLayerScrollableArea final
     return scrolling_background_display_item_client_;
   }
 
-  void PreFinalize() override;
+  void DisposeImpl() override;
   
  private:
   bool NeedsScrollbarReconstruction() const;

third_party/blink/renderer/core/scroll/scroll_animator_test.cc

@@ -139,8 +139,9 @@ class MockScrollableAreaForAnimatorTest
     ScrollableArea::Trace(visitor);
   }
 
-  virtual void PreFinalize() {
+  void DisposeImpl() override {
       timer_task_runner_.reset();
+      ScrollableArea::DisposeImpl();
   }
 
  private:

third_party/blink/renderer/core/scroll/scrollable_area.cc

@@ -96,13 +96,14 @@ ScrollableArea::ScrollableArea()
 ScrollableArea::~ScrollableArea() = default;
 
 void ScrollableArea::Dispose() {
+  DisposeImpl();
+}
+
+void ScrollableArea::DisposeImpl() {
   RunScrollCompleteCallbacks();
   fade_overlay_scrollbars_timer_.reset();
-  PreFinalize();
 }
 
-void ScrollableArea::PreFinalize() {}
-
 void ScrollableArea::ClearScrollableArea() {
 #if defined(OS_MACOSX)
   if (scroll_animator_)

third_party/blink/renderer/core/scroll/scrollable_area.h

@@ -351,7 +351,7 @@ class CORE_EXPORT ScrollableArea : public GarbageCollectedMixin {
   virtual ~ScrollableArea();
 
   void Dispose();
-  virtual void PreFinalize();
+  virtual void DisposeImpl();
 
   // Called when any of horizontal scrollbar, vertical scrollbar and scroll
   // corner is setNeedsPaintInvalidation.