Move ScrollbarManager from core to platform and use as Scrollbar parent

third_party/WebKit/Source/core/frame/FrameView.cpp

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 2cfd1d97e78a89a94c185f8208f98788d830eb23..cec8902c899bd0a6420250d83ba0b395333cb2b4 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -206,7 +206,6 @@ FrameView::FrameView(LocalFrame& frame)
       current_update_lifecycle_phases_target_state_(
           DocumentLifecycle::kUninitialized),
       scroll_anchor_(this),
-      scrollbar_manager_(*this),
       needs_scrollbars_update_(false),
       suppress_adjust_view_size_(false),
       allows_layout_invalidation_after_layout_clean_(true),
@@ -246,7 +245,6 @@ DEFINE_TRACE(FrameView) {
   visitor->Trace(visibility_observer_);
   visitor->Trace(scroll_anchor_);
   visitor->Trace(anchoring_adjustment_queue_);
-  visitor->Trace(scrollbar_manager_);
   visitor->Trace(print_context_);
   FrameViewBase::Trace(visitor);
   ScrollableArea::Trace(visitor);
@@ -401,7 +399,7 @@ void FrameView::DetachScrollbars() {
   // However, for Oilpan, we still need to remove the native scrollbars before
   // we lose the connection to the ChromeClient, so we just unconditionally
   // detach any scrollbars now.
-  scrollbar_manager_.Dispose();
+  ScrollbarManager::Dispose();
 
   if (scroll_corner_) {
     scroll_corner_->Destroy();
@@ -409,8 +407,7 @@ void FrameView::DetachScrollbars() {
   }
 }
 
-void FrameView::ScrollbarManager::SetHasHorizontalScrollbar(
-    bool has_scrollbar) {
+void FrameView::SetHasHorizontalScrollbar(bool has_scrollbar) {
   if (has_scrollbar == HasHorizontalScrollbar())
     return;
 
@@ -429,7 +426,7 @@ void FrameView::ScrollbarManager::SetHasHorizontalScrollbar(
   scrollable_area_->SetScrollCornerNeedsPaintInvalidation();
 }
 
-void FrameView::ScrollbarManager::SetHasVerticalScrollbar(bool has_scrollbar) {
+void FrameView::SetHasVerticalScrollbar(bool has_scrollbar) {
   if (has_scrollbar == HasVerticalScrollbar())
     return;
 
@@ -448,8 +445,7 @@ void FrameView::ScrollbarManager::SetHasVerticalScrollbar(bool has_scrollbar) {
   scrollable_area_->SetScrollCornerNeedsPaintInvalidation();
 }
 
-Scrollbar* FrameView::ScrollbarManager::CreateScrollbar(
-    ScrollbarOrientation orientation) {
+Scrollbar* FrameView::CreateScrollbar(ScrollbarOrientation orientation) {
   Element* custom_scrollbar_element = nullptr;
   LayoutBox* box = scrollable_area_->GetLayoutBox();
   if (box->GetDocument().View()->ShouldUseCustomScrollbars(
@@ -464,8 +460,7 @@ Scrollbar* FrameView::ScrollbarManager::CreateScrollbar(
                            &box->GetFrame()->GetPage()->GetChromeClient());
 }
 
-void FrameView::ScrollbarManager::DestroyScrollbar(
-    ScrollbarOrientation orientation) {
+void FrameView::DestroyScrollbar(ScrollbarOrientation orientation) {
   Member<Scrollbar>& scrollbar =
       orientation == kHorizontalScrollbar ? h_bar_ : v_bar_;
   DCHECK(orientation == kHorizontalScrollbar ? !h_bar_is_attached_
@@ -498,8 +493,8 @@ void FrameView::RecalculateCustomScrollbarStyle() {
 }
 
 void FrameView::InvalidateAllCustomScrollbarsOnActiveChanged() {
-  bool uses_window_inactive_selector =
-      frame_->GetDocument()->GetStyleEngine().UsesWindowInactiveSelector();
+  if (!frame_->GetDocument()->GetStyleEngine().UsesWindowInactiveSelector())
+    return;
 
   const ChildrenSet* view_children = Children();
   for (const Member<FrameViewBase>& child : *view_children) {
@@ -511,12 +506,10 @@ void FrameView::InvalidateAllCustomScrollbarsOnActiveChanged() {
   }
 
   for (const Member<Scrollbar>& scrollbar : *Scrollbars()) {
-    if (uses_window_inactive_selector && scrollbar->IsCustomScrollbar())
-      scrollbar->StyleChanged();
+    scrollbar->StyleChanged();
   }
 
-  if (uses_window_inactive_selector)
-    RecalculateCustomScrollbarStyle();
+  RecalculateCustomScrollbarStyle();
 }
 
 void FrameView::Clear() {
@@ -700,10 +693,6 @@ bool FrameView::ShouldUseCustomScrollbars(
   return false;
 }
 
-Scrollbar* FrameView::CreateScrollbar(ScrollbarOrientation orientation) {
-  return scrollbar_manager_.CreateScrollbar(orientation);
-}
-
 void FrameView::SetContentsSize(const IntSize& size) {
   if (size == ContentsSize())
     return;
@@ -2900,9 +2889,8 @@ void FrameView::VisualViewportScrollbarsChanged() {
   bool should_have_vertical_scrollbar = false;
   ComputeScrollbarExistence(should_have_horizontal_scrollbar,
                             should_have_vertical_scrollbar, ContentsSize());
-  scrollbar_manager_.SetHasHorizontalScrollbar(
-      should_have_horizontal_scrollbar);
-  scrollbar_manager_.SetHasVerticalScrollbar(should_have_vertical_scrollbar);
+  SetHasHorizontalScrollbar(should_have_horizontal_scrollbar);
+  SetHasVerticalScrollbar(should_have_vertical_scrollbar);
 
   if (has_horizontal_scrollbar != should_have_horizontal_scrollbar ||
       has_vertical_scrollbar != should_have_vertical_scrollbar) {
@@ -4278,8 +4266,8 @@ bool FrameView::AdjustScrollbarExistence(
   if (!scrollbar_existence_changed)
     return false;
 
-  scrollbar_manager_.SetHasHorizontalScrollbar(new_has_horizontal_scrollbar);
-  scrollbar_manager_.SetHasVerticalScrollbar(new_has_vertical_scrollbar);
+  SetHasHorizontalScrollbar(new_has_horizontal_scrollbar);
+  SetHasVerticalScrollbar(new_has_vertical_scrollbar);
 
   if (scrollbars_suppressed_)
     return true;
@@ -4341,8 +4329,8 @@ void FrameView::UpdateScrollbars() {
 
   // Avoid drawing two sets of scrollbars when visual viewport is enabled.
   if (VisualViewportSuppliesScrollbars()) {
-    scrollbar_manager_.SetHasHorizontalScrollbar(false);
-    scrollbar_manager_.SetHasVerticalScrollbar(false);
+    SetHasHorizontalScrollbar(false);
+    SetHasVerticalScrollbar(false);
     AdjustScrollOffsetFromUpdateScrollbars();
     return;
   }
@@ -4354,8 +4342,8 @@ void FrameView::UpdateScrollbars() {
   bool scrollbar_existence_changed = false;
 
   if (NeedsScrollbarReconstruction()) {
-    scrollbar_manager_.SetHasHorizontalScrollbar(false);
-    scrollbar_manager_.SetHasVerticalScrollbar(false);
+    SetHasHorizontalScrollbar(false);
+    SetHasVerticalScrollbar(false);
     scrollbar_existence_changed = true;
   }