Correct for enclosing layers scroll position in sticky_data->main_thread_offset

cc/trees/layer_tree_host_common_unittest.cc

Index: cc/trees/layer_tree_host_common_unittest.cc
diff --git a/cc/trees/layer_tree_host_common_unittest.cc b/cc/trees/layer_tree_host_common_unittest.cc
index 969398354c27a08fbe0a5efc614eac2302d1ede4..4b76c2f960e49ef0553e92f57ae40988a382416d 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -7651,7 +7651,8 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionMainThreadUpdates) {
 
 // This tests the main thread updates with a composited sticky container. In
 // this case the position received from main is relative to the container but
-// the constraint rects are relative to the ancestor scroller.
+// the constraint rects are relative to the ancestor scroller. The
+// parent_relative_sticky_box_offset from main also includes the scroll offset.
 TEST_F(LayerTreeHostCommonTest, StickyPositionCompositedContainer) {
   scoped_refptr<Layer> root = Layer::Create();
   scoped_refptr<Layer> container = Layer::Create();
@@ -7719,6 +7720,8 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionCompositedContainer) {
 
   // Now the main thread commits the new position of the sticky element.
   scroller->SetScrollOffset(gfx::ScrollOffset(0, 25));
+  sticky_position.parent_relative_sticky_box_offset += gfx::Vector2d(0, 25);
+  sticky_pos->SetStickyPositionConstraint(sticky_position);
   sticky_pos->SetPosition(gfx::PointF(0, 15));
   ExecuteCalculateDrawProperties(root.get());
   host()->host_impl()->CreatePendingTree();