Add convenience methods for PLSA visible client dimensions.

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@gmail.com>
@@ skipping 537 matching lines @@
 }
 
 int PaintLayerScrollableArea::VisibleHeight() const {
   return Layer()->size().Height();
 }
 
 int PaintLayerScrollableArea::VisibleWidth() const {
   return Layer()->size().Width();
 }
 
+LayoutSize PaintLayerScrollableArea::ClientSize() const {
+  if (RuntimeEnabledFeatures::rootLayerScrollingEnabled()) {
+    bool is_main_frame_root_layer =
+        layer_.IsRootLayer() && Box().GetDocument().GetFrame()->IsMainFrame();
+    if (is_main_frame_root_layer) {
+      LayoutSize result(Box().GetFrameView()->GetLayoutSize());
+      result -= IntSize(VerticalScrollbarWidth(), HorizontalScrollbarHeight());
+      return result;
+    }
+  }
+  return LayoutSize(Box().ClientWidth(), Box().ClientHeight());
+}
+
+IntSize PaintLayerScrollableArea::PixelSnappedClientSize() const {
+  if (RuntimeEnabledFeatures::rootLayerScrollingEnabled()) {
+    bool is_main_frame_root_layer =
+        layer_.IsRootLayer() && Box().GetDocument().GetFrame()->IsMainFrame();
+    if (is_main_frame_root_layer) {
+      return ExcludeScrollbars(Box().GetFrameView()->GetLayoutSize());
+    }
+  }
+  return IntSize(Box().PixelSnappedClientWidth(),
+                 Box().PixelSnappedClientHeight());
+}
+
 IntSize PaintLayerScrollableArea::ContentsSize() const {
   return IntSize(PixelSnappedScrollWidth(), PixelSnappedScrollHeight());
 }
 
 void PaintLayerScrollableArea::ContentsResized() {
   ScrollableArea::ContentsResized();
   // Need to update the bounds of the scroll property.
   Box().SetNeedsPaintPropertyUpdate();
 }
 
@@ skipping 252 matching lines @@
 
   {
     // Hits in
     // compositing/overflow/automatically-opt-into-composited-scrolling-after-style-change.html.
     DisableCompositingQueryAsserts disabler;
 
     UpdateScrollbarEnabledState();
 
     // Set up the range (and page step/line step).
     if (Scrollbar* horizontal_scrollbar = this->HorizontalScrollbar()) {
-      int client_width = Box().PixelSnappedClientWidth();
+      int client_width = PixelSnappedClientSize().Width();
       horizontal_scrollbar->SetProportion(client_width,
                                           OverflowRect().Width().ToInt());
     }
     if (Scrollbar* vertical_scrollbar = this->VerticalScrollbar()) {
-      int client_height = Box().PixelSnappedClientHeight();
+      int client_height = PixelSnappedClientSize().Height();
       vertical_scrollbar->SetProportion(client_height,
                                         OverflowRect().Height().ToInt());
     }
   }
 
   if (!scrollbars_are_frozen && HasOverlayScrollbars()) {
     if (!ScrollSize(kHorizontalScrollbar))
       SetHasHorizontalScrollbar(false);
     if (!ScrollSize(kVerticalScrollbar))
       SetHasVerticalScrollbar(false);
@@ skipping 76 matching lines @@
 
 bool PaintLayerScrollableArea::HasHorizontalOverflow() const {
   // TODO(szager): Make the algorithm for adding/subtracting overflow:auto
   // scrollbars memoryless (crbug.com/625300).  This clientWidth hack will
   // prevent the spurious horizontal scrollbar, but it can cause a converse
   // problem: it can leave a sliver of horizontal overflow hidden behind the
   // vertical scrollbar without creating a horizontal scrollbar.  This
   // converse problem seems to happen much less frequently in practice, so we
   // bias the logic towards preventing unwanted horizontal scrollbars, which
   // are more common and annoying.
-  int client_width = Box().PixelSnappedClientWidth();
+  int client_width = PixelSnappedClientSize().Width();
   if (NeedsRelayout() && !HadVerticalScrollbarBeforeRelayout())
     client_width += VerticalScrollbarWidth();
   return PixelSnappedScrollWidth() > client_width;
 }
 
 bool PaintLayerScrollableArea::HasVerticalOverflow() const {
-  return PixelSnappedScrollHeight() > Box().PixelSnappedClientHeight();
+  return PixelSnappedScrollHeight() > PixelSnappedClientSize().Height();
 }
 
 bool PaintLayerScrollableArea::HasScrollableHorizontalOverflow() const {
   return HasHorizontalOverflow() && Box().ScrollsOverflowX();
 }
 
 bool PaintLayerScrollableArea::HasScrollableVerticalOverflow() const {
   return HasVerticalOverflow() && Box().ScrollsOverflowY();
 }
 
@@ skipping 87 matching lines @@
   const bool layers_changed =
       topmost_scroll_child_ != next_topmost_scroll_child_;
   topmost_scroll_child_ = next_topmost_scroll_child_;
   next_topmost_scroll_child_ = nullptr;
   return layers_changed;
 }
 
 void PaintLayerScrollableArea::UpdateAfterOverflowRecalc() {
   UpdateScrollDimensions();
   if (Scrollbar* horizontal_scrollbar = this->HorizontalScrollbar()) {
-    int client_width = Box().PixelSnappedClientWidth();
+    int client_width = PixelSnappedClientSize().Width();
     horizontal_scrollbar->SetProportion(client_width,
                                         OverflowRect().Width().ToInt());
   }
   if (Scrollbar* vertical_scrollbar = this->VerticalScrollbar()) {
-    int client_height = Box().PixelSnappedClientHeight();
+    int client_height = PixelSnappedClientSize().Height();
     vertical_scrollbar->SetProportion(client_height,
                                       OverflowRect().Height().ToInt());
   }
 
   bool needs_horizontal_scrollbar;
   bool needs_vertical_scrollbar;
   ComputeScrollbarExistence(needs_horizontal_scrollbar,
                             needs_vertical_scrollbar);
 
   bool horizontal_scrollbar_should_change =
@@ skipping 634 matching lines @@
 LayoutRect PaintLayerScrollableArea::ScrollIntoView(
     const LayoutRect& rect,
     const ScrollAlignment& align_x,
     const ScrollAlignment& align_y,
     ScrollType scroll_type) {
   LayoutRect local_expose_rect(
       Box()
           .AbsoluteToLocalQuad(FloatQuad(FloatRect(rect)), kUseTransforms)
           .BoundingBox());
   local_expose_rect.Move(-Box().BorderLeft(), -Box().BorderTop());
-  LayoutRect layer_bounds(
-      LayoutPoint(), LayoutSize(Box().ClientWidth(), Box().ClientHeight()));
+  LayoutRect visible_rect(LayoutPoint(), ClientSize());
   LayoutRect r = ScrollAlignment::GetRectToExpose(
-      layer_bounds, local_expose_rect, align_x, align_y);
+      visible_rect, local_expose_rect, align_x, align_y);
 
   ScrollOffset old_scroll_offset = GetScrollOffset();
   ScrollOffset new_scroll_offset(ClampScrollOffset(RoundedIntSize(
       ToScrollOffset(FloatPoint(r.Location()) + old_scroll_offset))));
   SetScrollOffset(new_scroll_offset, scroll_type, kScrollBehaviorInstant);
   ScrollOffset scroll_offset_difference = GetScrollOffset() - old_scroll_offset;
   local_expose_rect.Move(-LayoutSize(scroll_offset_difference));
 
   LayoutRect intersect =
-      LocalToAbsolute(Box(), Intersection(layer_bounds, local_expose_rect));
-  if (intersect.IsEmpty() && !layer_bounds.IsEmpty() &&
+      LocalToAbsolute(Box(), Intersection(visible_rect, local_expose_rect));
+  if (intersect.IsEmpty() && !visible_rect.IsEmpty() &&
       !local_expose_rect.IsEmpty()) {
     return LocalToAbsolute(Box(), local_expose_rect);
   }
   return intersect;
 }
 
 void PaintLayerScrollableArea::UpdateScrollableAreaSet(bool has_overflow) {
   LocalFrame* frame = Box().GetFrame();
   if (!frame)
     return;
@@ skipping 417 matching lines @@
 
 void PaintLayerScrollableArea::DelayScrollOffsetClampScope::
     ClampScrollableAreas() {
   for (auto& scrollable_area : *needs_clamp_)
     scrollable_area->ClampScrollOffsetAfterOverflowChange();
   delete needs_clamp_;
   needs_clamp_ = nullptr;
 }
 
 }  // namespace blink