Delete LocalFrameView::ScrollbarManager and scroll_corner_.

This removes methods and paths in LocalFrameView that depend directly on
scrollbar existence.  Since RLS, LocalFrameView never has scrollbars.

Bug: 823365
Change-Id: I691480e4cad9239f12c50aa868c5d13571d45b2f
Reviewed-on: https://chromium-review.googlesource.com/1097540Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Steve Kobes <skobes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566618}

third_party/blink/renderer/core/dom/document.cc

@@ -2043,7 +2043,6 @@ void Document::PropagateStyleToViewport() {
 
     View()->RecalculateScrollbarOverlayColorTheme(
         View()->DocumentBackgroundColor());
-    View()->RecalculateCustomScrollbarStyle();
     if (PaintLayerScrollableArea* scrollable_area =
             GetLayoutView()->GetScrollableArea()) {
       if (scrollable_area->HorizontalScrollbar() &&

third_party/blink/renderer/core/exported/web_view_impl.cc

@@ -3607,9 +3607,6 @@ void WebViewImpl::ApplyViewportDeltas(
   }
 
   elastic_overscroll_ += elastic_overscroll_delta;
-
-  if (MainFrameImpl() && MainFrameImpl()->GetFrameView())
-    MainFrameImpl()->GetFrameView()->DidUpdateElasticOverscroll();
 }
 
 void WebViewImpl::RecordWheelAndTouchScrollingCount(

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

@@ -49,7 +49,6 @@
 #include "third_party/blink/renderer/core/paint/object_paint_properties.h"
 #include "third_party/blink/renderer/core/paint/paint_invalidation_capable_scrollable_area.h"
 #include "third_party/blink/renderer/core/paint/paint_phase.h"
-#include "third_party/blink/renderer/core/paint/scrollbar_manager.h"
 #include "third_party/blink/renderer/platform/geometry/int_rect.h"
 #include "third_party/blink/renderer/platform/geometry/layout_rect.h"
 #include "third_party/blink/renderer/platform/graphics/color.h"
@@ -57,7 +56,6 @@
 #include "third_party/blink/renderer/platform/graphics/graphics_layer_client.h"
 #include "third_party/blink/renderer/platform/runtime_enabled_features.h"
 #include "third_party/blink/renderer/platform/scroll/scroll_types.h"
-#include "third_party/blink/renderer/platform/scroll/scrollbar.h"
 #include "third_party/blink/renderer/platform/scroll/smooth_scroll_sequencer.h"
 #include "third_party/blink/renderer/platform/ukm_time_aggregator.h"
 #include "third_party/blink/renderer/platform/wtf/allocator.h"
@@ -154,8 +152,6 @@ class CORE_EXPORT LocalFrameView final
   void SetCanHaveScrollbars(bool);
   bool CanHaveScrollbars() const { return can_have_scrollbars_; }
 
-  Scrollbar* CreateScrollbar(ScrollbarOrientation) override;
-
   void SnapAfterScrollbarDragging(ScrollbarOrientation) override;
 
   void SetLayoutOverflowSize(const IntSize&);
@@ -223,8 +219,6 @@ class CORE_EXPORT LocalFrameView final
   void UpdateCountersAfterStyleChange();
 
   void Dispose() override;
-  void DetachScrollbars();
-  void RecalculateCustomScrollbarStyle();
   void InvalidateAllCustomScrollbarsOnActiveChanged();
 
   // True if the LocalFrameView's base background color is completely opaque.
@@ -244,7 +238,6 @@ class CORE_EXPORT LocalFrameView final
   void SetInputEventsScaleForEmulation(float);
 
   void DidChangeScrollOffset();
-  void DidUpdateElasticOverscroll();
 
   void ViewportSizeChanged(bool width_changed, bool height_changed);
   void MarkViewportConstrainedObjectsForLayout(bool width_changed,
@@ -389,10 +382,6 @@ class CORE_EXPORT LocalFrameView final
   FloatPoint ConvertToLayoutObject(const LayoutObject&,
                                    const FloatPoint&) const;
 
-  bool IsFrameViewScrollCorner(LayoutScrollbarPart* scroll_corner) const {
-    return scroll_corner_ == scroll_corner;
-  }
-
   enum ScrollingReasons {
     kScrollable,
     kNotScrollableNoOverflow,
@@ -402,7 +391,6 @@ class CORE_EXPORT LocalFrameView final
 
   ScrollingReasons GetScrollingReasons() const;
   bool IsScrollable() const override;
-  bool IsProgrammaticallyScrollable() override;
 
   IntPoint LastKnownMousePosition() const override;
   bool ShouldSetCursor() const;
@@ -473,7 +461,7 @@ class CORE_EXPORT LocalFrameView final
   bool ShouldScrollOnMainThread() const override;
   PaintLayer* Layer() const override;
   int ScrollSize(ScrollbarOrientation) const override;
-  bool IsScrollCornerVisible() const override;
+  bool IsScrollCornerVisible() const override { return false; }
   bool UpdateAfterCompositingChange() override;
   bool UserInputScrollable(ScrollbarOrientation) const override {
     return false;
@@ -521,18 +509,7 @@ class CORE_EXPORT LocalFrameView final
   void RemoveScrollbar(Scrollbar*);
   void AddScrollbar(Scrollbar*);
 
-  // If the scroll view does not use a native widget, then it will have
-  // cross-platform Scrollbars. These functions can be used to obtain those
-  // scrollbars.
-  Scrollbar* HorizontalScrollbar() const override {
-    return scrollbar_manager_.HorizontalScrollbar();
-  }
-  Scrollbar* VerticalScrollbar() const override {
-    return scrollbar_manager_.VerticalScrollbar();
-  }
-  LayoutScrollbarPart* ScrollCorner() const override { return scroll_corner_; }
-
-  void PositionScrollbarLayers();
+  LayoutScrollbarPart* ScrollCorner() const override { return nullptr; }
 
   // Functions for setting and retrieving the scrolling mode in each axis
   // (horizontal/vertical). The mode has values of AlwaysOff, AlwaysOn, and
@@ -639,10 +616,6 @@ class CORE_EXPORT LocalFrameView final
   // Functions for converting to screen coordinates.
   IntRect ContentsToScreen(const IntRect&) const;
 
-  // For platforms that need to hit test scrollbars from within the engine's
-  // event handlers (like Win32).
-  Scrollbar* ScrollbarAtFramePoint(const IntPoint&);
-
   // Converts from/to local "frame" coordinates to the root "frame"
   // coordinates. Note: with root-layer-scrolls, "frame" coordinates become
   // equivalent to "absoltue" coordinates since the LayoutView (same size and
@@ -702,9 +675,7 @@ class CORE_EXPORT LocalFrameView final
   void Show() override;
   void Hide() override;
 
-  bool IsPointInScrollbarCorner(const IntPoint&);
-  bool ScrollbarCornerPresent() const;
-  IntRect ScrollCornerRect() const override;
+  IntRect ScrollCornerRect() const override { return IntRect(); }
 
   IntPoint ConvertFromContainingEmbeddedContentViewToScrollbar(
       const Scrollbar&,
@@ -820,8 +791,7 @@ class CORE_EXPORT LocalFrameView final
 
   void CrossOriginStatusChanged();
 
-  // The visual viewport can supply scrollbars which affect the existence of
-  // our scrollbars (see: computeScrollbarExistence).
+  // The visual viewport can supply scrollbars.
   void VisualViewportScrollbarsChanged();
 
   LayoutUnit CaretWidth() const;
@@ -876,44 +846,8 @@ class CORE_EXPORT LocalFrameView final
 
   void NotifyFrameRectsChangedIfNeeded();
 
-  enum ComputeScrollbarExistenceOption { kFirstPass, kIncremental };
-  void ComputeScrollbarExistence(bool& new_has_horizontal_scrollbar,
-                                 bool& new_has_vertical_scrollbar,
-                                 const IntSize& doc_size,
-                                 ComputeScrollbarExistenceOption = kFirstPass);
-  void UpdateScrollbarGeometry();
-
-  class InUpdateScrollbarsScope {
-    STACK_ALLOCATED();
-
-   public:
-    explicit InUpdateScrollbarsScope(LocalFrameView* view)
-        : scope_(&view->in_update_scrollbars_, true) {}
-
-   private:
-    base::AutoReset<bool> scope_;
-  };
-
  private:
   explicit LocalFrameView(LocalFrame&, IntRect);
-  class ScrollbarManager : public blink::ScrollbarManager {
-    DISALLOW_NEW();
-
-    // Helper class to manage the life cycle of Scrollbar objects.
-   public:
-    ScrollbarManager(LocalFrameView& scroller)
-        : blink::ScrollbarManager(scroller) {}
-
-    void SetHasHorizontalScrollbar(bool has_scrollbar) override;
-    void SetHasVerticalScrollbar(bool has_scrollbar) override;
-
-    // TODO(ymalik): This should be hidden and all calls should go through
-    // setHas*Scrollbar functions above.
-    Scrollbar* CreateScrollbar(ScrollbarOrientation) override;
-
-   protected:
-    void DestroyScrollbar(ScrollbarOrientation) override;
-  };
 
   void PaintInternal(GraphicsContext&,
                      const GlobalPaintFlags,
@@ -924,8 +858,6 @@ class CORE_EXPORT LocalFrameView final
 
   void UpdateScrollOffset(const ScrollOffset&, ScrollType) override;
 
-  void UpdateScrollbarEnabledState();
-
   void DispatchEventsForPrintingOnAllFrames();
 
   void SetupPrintContext();
@@ -961,7 +893,6 @@ class CORE_EXPORT LocalFrameView final
   DocumentLifecycle& Lifecycle() const;
 
   void ContentsResized() override;
-  void ScrollbarExistenceMaybeChanged();
 
   // Methods to do point conversion via layoutObjects, in order to take
   // transforms into account.
@@ -993,28 +924,17 @@ class CORE_EXPORT LocalFrameView final
   void UpdateCompositedSelectionIfNeeded();
   void SetNeedsCompositingUpdate(CompositingUpdateType);
 
-  // Returns true if the LocalFrameView's own scrollbars overlay its content
-  // when visible.
-  bool HasOverlayScrollbars() const;
-
   // Returns true if the frame should use custom scrollbars. If true, sets
   // customScrollbarElement to the element that supplies the scrollbar's style
   // information.
   bool ShouldUseCustomScrollbars(Element*& custom_scrollbar_element) const;
 
-  // Returns true if a scrollbar needs to go from native -> custom or vice
-  // versa, or if a custom scrollbar has a stale owner.
-  bool NeedsScrollbarReconstruction() const;
-
   bool ShouldIgnoreOverflowHidden() const;
 
-  void UpdateScrollCorner();
-
   AXObjectCache* ExistingAXObjectCache() const;
 
   void SetLayoutSizeInternal(const IntSize&);
 
-  void AdjustScrollbarOpacity();
   bool VisualViewportSuppliesScrollbars();
 
   ScrollingCoordinator* GetScrollingCoordinator() const;
@@ -1101,9 +1021,6 @@ class CORE_EXPORT LocalFrameView final
 
   Member<Node> fragment_anchor_;
 
-  // layoutObject to hold our custom scroll corner.
-  LayoutScrollbarPart* scroll_corner_;
-
   Member<ScrollableAreaSet> scrollable_areas_;
   Member<ScrollableAreaSet> animating_scrollable_areas_;
   std::unique_ptr<ResizerAreaSet> resizer_areas_;
@@ -1141,7 +1058,6 @@ class CORE_EXPORT LocalFrameView final
 
   bool scrollbars_suppressed_;
   bool root_layer_did_scroll_;
-  bool in_update_scrollbars_;
 
   std::unique_ptr<LayoutAnalyzer> analyzer_;
 
@@ -1171,9 +1087,6 @@ class CORE_EXPORT LocalFrameView final
       HeapLinkedHashSet<WeakMember<ScrollableArea>>;
   AnchoringAdjustmentQueue anchoring_adjustment_queue_;
 
-  // ScrollbarManager holds the Scrollbar instances.
-  ScrollbarManager scrollbar_manager_;
-
   bool suppress_adjust_view_size_;
   bool allows_layout_invalidation_after_layout_clean_;
   bool needs_intersection_observation_;

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

@@ -669,12 +669,6 @@ WebInputEventResult MouseEventManager::HandleMousePressEvent(
 
   frame_->GetDocument()->UpdateStyleAndLayoutIgnorePendingStylesheets();
 
-  if (LocalFrameView* frame_view = frame_->View()) {
-    if (frame_view->IsPointInScrollbarCorner(
-            FlooredIntPoint(event.Event().PositionInRootFrame())))
-      return WebInputEventResult::kNotHandled;
-  }
-
   bool single_click = event.Event().click_count <= 1;
 
   mouse_down_may_start_drag_ =

third_party/blink/renderer/core/layout/layout_embedded_content.cc

@@ -256,12 +256,6 @@ void LayoutEmbeddedContent::StyleDidChange(StyleDifference diff,
   if (!embedded_content_view)
     return;
 
-  // If the iframe has custom scrollbars, recalculate their style.
-  if (FrameView* frame_view = ChildFrameView()) {
-    if (frame_view->IsLocalFrameView())
-      ToLocalFrameView(frame_view)->RecalculateCustomScrollbarStyle();
-  }
-
   if (Style()->Visibility() != EVisibility::kVisible) {
     embedded_content_view->Hide();
   } else {

third_party/blink/renderer/core/layout/layout_scrollbar_part.cc

@@ -233,13 +233,6 @@ void LayoutScrollbarPart::SetNeedsPaintInvalidation() {
 
   // This LayoutScrollbarPart is a scroll corner or a resizer.
   DCHECK_EQ(part_, kNoPart);
-  if (LocalFrameView* frame_view = View()->GetFrameView()) {
-    if (frame_view->IsFrameViewScrollCorner(this)) {
-      frame_view->SetScrollCornerNeedsPaintInvalidation();
-      return;
-    }
-  }
-
   scrollable_area_->SetScrollCornerNeedsPaintInvalidation();
 }
 

third_party/blink/renderer/core/layout/layout_view.cc

@@ -144,19 +144,6 @@ bool LayoutView::HitTestNoLifecycleUpdate(HitTestResult& result) {
   } else {
     hit_layer = Layer()->HitTest(result);
 
-    // LocalFrameView scrollbars are not the same as Layer scrollbars tested by
-    // Layer::hitTestOverflowControls, so we need to test LocalFrameView
-    // scrollbars separately here. Note that it's important we do this after the
-    // hit test above, because that may overwrite the entire HitTestResult when
-    // it finds a hit.
-    IntPoint frame_point = GetFrameView()->ContentsToFrame(
-        result.GetHitTestLocation().RoundedPoint());
-    if (Scrollbar* frame_scrollbar =
-            GetFrameView()->ScrollbarAtFramePoint(frame_point)) {
-      result.SetScrollbar(frame_scrollbar);
-      hit_layer = true;
-    }
-
     // If hitTestResult include scrollbar, innerNode should be the parent of the
     // scrollbar.
     if (result.GetScrollbar()) {