Remove use of GraphicsLayer::GetPosition from test

Modifying unit tests to validate that the layers are positioned properly
via the transform property tree or offset from transform node instead of
via checking GraphicsLayer's position.  This is in preparation for
removing GraphicsLayer's GetPosition entirely.


Bug: 999336
Change-Id: Ib591083846f411fe7bd9e3ad7180b16ed2f2573d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1897131
Commit-Queue: Sam Fortiner <samfort@microsoft.com>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712340}

third_party/blink/renderer/core/paint/compositing/composited_layer_mapping_test.cc

@@ -14,6 +14,7 @@
 #include "third_party/blink/renderer/core/paint/paint_layer.h"
 #include "third_party/blink/renderer/core/paint/paint_layer_scrollable_area.h"
 #include "third_party/blink/renderer/core/testing/core_unit_test_helper.h"
+#include "third_party/blink/renderer/platform/graphics/paint/geometry_mapper.h"
 
 namespace blink {
 
@@ -1251,10 +1252,22 @@ TEST_F(CompositedLayerMappingTest,
   // the sticky element.
   EXPECT_EQ(PhysicalOffset(0, 100), sticky->StickyPositionOffset());
 
-  // On the CompositedLayerMapping side however, the offset should have been
-  // removed so that the compositor can take care of it.
-  EXPECT_FLOAT_EQ(0, main_graphics_layer->GetPosition().x());
-  EXPECT_FLOAT_EQ(0, main_graphics_layer->GetPosition().y());
+  GraphicsLayer* root_scrolling_layer =
+      GetDocument().GetLayoutView()->Layer()->GraphicsLayerBacking();
+  const PropertyTreeState& root_layer_state =
+      root_scrolling_layer->GetPropertyTreeState();
+  const PropertyTreeState& sticky_layer_state =
+      main_graphics_layer->GetPropertyTreeState();
+  auto transform_from_sticky_to_root =
+      GeometryMapper::SourceToDestinationProjection(
+          sticky_layer_state.Transform(), root_layer_state.Transform());
+  // Irrespective of if the ancestor scroller is composited or not, the sticky
+  // position element should be at the same location.
+  auto sticky_position_relative_to_root =
+      transform_from_sticky_to_root.MapPoint(
+          FloatPoint(main_graphics_layer->GetOffsetFromTransformNode()));
+  EXPECT_FLOAT_EQ(8, sticky_position_relative_to_root.X());
+  EXPECT_FLOAT_EQ(8, sticky_position_relative_to_root.Y());
 }
 
 TEST_F(CompositedLayerMappingTest,
@@ -1287,8 +1300,22 @@ TEST_F(CompositedLayerMappingTest,
       FloatPoint(scrollable_area->ScrollPosition().Y(), 100));
   UpdateAllLifecyclePhasesForTest();
 
-  EXPECT_FLOAT_EQ(0, main_graphics_layer->GetPosition().x());
-  EXPECT_FLOAT_EQ(100, main_graphics_layer->GetPosition().y());
+  GraphicsLayer* root_scrolling_layer =
+      GetDocument().GetLayoutView()->Layer()->GraphicsLayerBacking();
+  const PropertyTreeState& root_layer_state =
+      root_scrolling_layer->GetPropertyTreeState();
+  const PropertyTreeState& sticky_layer_state =
+      main_graphics_layer->GetPropertyTreeState();
+  auto transform_from_sticky_to_root =
+      GeometryMapper::SourceToDestinationProjection(
+          sticky_layer_state.Transform(), root_layer_state.Transform());
+  // Irrespective of if the ancestor scroller is composited or not, the sticky
+  // position element should be at the same location.
+  auto sticky_position_relative_to_root =
+      transform_from_sticky_to_root.MapPoint(
+          FloatPoint(main_graphics_layer->GetOffsetFromTransformNode()));
+  EXPECT_FLOAT_EQ(8, sticky_position_relative_to_root.X());
+  EXPECT_FLOAT_EQ(8, sticky_position_relative_to_root.Y());
 }
 
 TEST_F(CompositedLayerMappingTest,
@@ -1565,8 +1592,8 @@ TEST_F(CompositedLayerMappingTest,
   UpdateAllLifecyclePhasesForTest();
 
   // 100px down from squashing's main graphics layer.
-  EXPECT_EQ(FloatPoint(0, 100),
-            squashed->GraphicsLayerBacking()->GetPosition());
+  EXPECT_EQ(IntPoint(0, 100),
+            squashed->GraphicsLayerBacking()->GetOffsetFromTransformNode());
 }
 
 TEST_F(CompositedLayerMappingTest, ContentsNotOpaqueWithForegroundLayer) {