Add sticky nodes affected by inner and outer viewport bounds deltas.

cc/trees/property_tree_builder.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/property_tree_builder.h"
 
 #include <stddef.h>
 
 #include <map>
 #include <set>
@@ skipping 651 matching lines @@
   if (is_overscroll_elasticity_layer) {
     DCHECK(!is_scrollable);
     node->scroll_offset =
         gfx::ScrollOffset(data_from_ancestor.elastic_overscroll);
   } else if (!ScrollParent(layer)) {
     node->scroll_offset = layer->CurrentScrollOffset();
   }
 
   if (is_fixed) {
     if (data_from_ancestor.affected_by_inner_viewport_bounds_delta) {
-      node->affected_by_inner_viewport_bounds_delta_x =
+      node->moved_by_inner_viewport_bounds_delta_x =
           PositionConstraint(layer).is_fixed_to_right_edge();
-      node->affected_by_inner_viewport_bounds_delta_y =
+      node->moved_by_inner_viewport_bounds_delta_y =
           PositionConstraint(layer).is_fixed_to_bottom_edge();
-      if (node->affected_by_inner_viewport_bounds_delta_x ||
-          node->affected_by_inner_viewport_bounds_delta_y) {
+      if (node->moved_by_inner_viewport_bounds_delta_x ||
+          node->moved_by_inner_viewport_bounds_delta_y) {
         data_for_children->property_trees->transform_tree
             .AddNodeAffectedByInnerViewportBoundsDelta(node->id);
       }
     } else if (data_from_ancestor.affected_by_outer_viewport_bounds_delta) {
-      node->affected_by_outer_viewport_bounds_delta_x =
+      node->moved_by_outer_viewport_bounds_delta_x =
           PositionConstraint(layer).is_fixed_to_right_edge();
-      node->affected_by_outer_viewport_bounds_delta_y =
+      node->moved_by_outer_viewport_bounds_delta_y =
           PositionConstraint(layer).is_fixed_to_bottom_edge();
-      if (node->affected_by_outer_viewport_bounds_delta_x ||
-          node->affected_by_outer_viewport_bounds_delta_y) {
+      if (node->moved_by_outer_viewport_bounds_delta_x ||
+          node->moved_by_outer_viewport_bounds_delta_y) {
         data_for_children->property_trees->transform_tree
             .AddNodeAffectedByOuterViewportBoundsDelta(node->id);
       }
     }
   }
 
   node->local = Transform(layer);
   node->update_pre_local_transform(TransformOrigin(layer));
 
   if (StickyPositionConstraint(layer).is_sticky) {
     StickyPositionNodeData* sticky_data =
         data_for_children->property_trees->transform_tree.StickyPositionData(
             node->id);
     sticky_data->constraints = StickyPositionConstraint(layer);
     sticky_data->scroll_ancestor = GetScrollParentId(data_from_ancestor, layer);
     ScrollNode* scroll_ancestor =
         data_for_children->property_trees->scroll_tree.Node(
             sticky_data->scroll_ancestor);
-    if (scroll_ancestor->is_inner_viewport_scroll_layer) {
-      data_for_children->property_trees->transform_tree
-          .AddNodeAffectedByInnerViewportBoundsDelta(node->id);
+    if (sticky_data->constraints.is_anchored_right ||
+        sticky_data->constraints.is_anchored_bottom) {
+      // Sticky nodes whose ancestor scroller is the inner / outer viewport
+      // need to have their local transform updated when the inner / outer
+      // viewport bounds change, but do not unconditionally move by that delta
+      // like fixed position nodes.
+      if (scroll_ancestor->is_inner_viewport_scroll_layer) {
+        data_for_children->property_trees->transform_tree
+            .AddNodeAffectedByInnerViewportBoundsDelta(node->id);
+      } else if (scroll_ancestor->is_outer_viewport_scroll_layer) {
+        data_for_children->property_trees->transform_tree
+            .AddNodeAffectedByOuterViewportBoundsDelta(node->id);
+      }
     }
     sticky_data->main_thread_offset =
         layer->position().OffsetFromOrigin() -
         sticky_data->constraints.parent_relative_sticky_box_offset
             .OffsetFromOrigin();
   }
 
   node->needs_local_transform_update = true;
   data_from_ancestor.property_trees->transform_tree.UpdateTransforms(node->id);
 
@@ skipping 762 matching lines @@
     color = SkColorSetA(color, 255);
   BuildPropertyTreesTopLevelInternal(
       root_layer, page_scale_layer, inner_viewport_scroll_layer,
       outer_viewport_scroll_layer, overscroll_elasticity_layer,
       elastic_overscroll, page_scale_factor, device_scale_factor, viewport,
       device_transform, property_trees, color);
   property_trees->ResetCachedData();
 }
 
 }  // namespace cc