Shifting layer position for sticky element to avoid passing unnessary variable to cc

cc/trees/layer_tree_host_common_unittest.cc

 // Copyright 2011 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/layer_tree_host_common.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <memory>
@@ skipping 6861 matching lines @@
 
   LayerStickyPositionConstraint sticky_position;
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_top = true;
   sticky_position.top_offset = 10.0f;
   sticky_position.scroll_container_relative_sticky_box_rect =
       gfx::Rect(10, 20, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
       gfx::Rect(0, 0, 50, 50);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
-  sticky_pos->SetElementId(LayerIdToElementIdForTesting(sticky_pos->id()));
 
   root->SetBounds(gfx::Size(100, 100));
   container->SetBounds(gfx::Size(100, 100));
   scroller->SetBounds(gfx::Size(1000, 1000));
   sticky_pos->SetBounds(gfx::Size(10, 10));
   sticky_pos->SetPosition(gfx::PointF(10, 20));
 
   ExecuteCalculateDrawProperties(root.get());
   host()->host_impl()->CreatePendingTree();
   host()->CommitAndCreatePendingTree();
@@ skipping 19 matching lines @@
 
   // Scroll past the sticking point, the Y coordinate should now be clamped.
   SetScrollOffsetDelta(scroller_impl, gfx::Vector2dF(15.f, 15.f));
   ExecuteCalculateDrawProperties(root_impl);
   EXPECT_VECTOR2DF_EQ(
       gfx::Vector2dF(-5.f, 10.f),
       sticky_pos_impl->ScreenSpaceTransform().To2dTranslation());
 
   // Now the main thread commits the new position of the sticky element.
   scroller->SetScrollOffset(gfx::ScrollOffset(15, 15));
-  sticky_pos->SetPosition(gfx::PointF(10, 25));
-  sticky_pos->SetOffsetForStickyPositionFromMainThread(gfx::Size(0, 5));
+  // Shift the layer by -offset_for_position_sticky.
+  sticky_pos->SetPosition(gfx::PointF(10, 25) - gfx::Vector2dF(0, 5));
   ExecuteCalculateDrawProperties(root.get());
   host()->host_impl()->CreatePendingTree();
   host()->CommitAndCreatePendingTree();
   host()->host_impl()->ActivateSyncTree();
   layer_tree_impl = host()->host_impl()->active_tree();
   root_impl = layer_tree_impl->LayerById(root->id());
   scroller_impl = layer_tree_impl->LayerById(scroller->id());
   sticky_pos_impl = layer_tree_impl->LayerById(sticky_pos->id());
 
   // The element should still be where it was before. We reset the delta to
@@ skipping 32 matching lines @@
 
   LayerStickyPositionConstraint sticky_position;
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_top = true;
   sticky_position.top_offset = 10.0f;
   sticky_position.scroll_container_relative_sticky_box_rect =
       gfx::Rect(20, 30, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
       gfx::Rect(20, 20, 30, 30);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
-  sticky_pos->SetElementId(LayerIdToElementIdForTesting(sticky_pos->id()));
 
   root->SetBounds(gfx::Size(100, 100));
   container->SetBounds(gfx::Size(100, 100));
   scroller->SetBounds(gfx::Size(1000, 1000));
   sticky_container->SetPosition(gfx::PointF(20, 20));
   sticky_container->SetBounds(gfx::Size(30, 30));
   sticky_pos->SetBounds(gfx::Size(10, 10));
   sticky_pos->SetPosition(gfx::PointF(0, 10));
 
   ExecuteCalculateDrawProperties(root.get());
@@ skipping 21 matching lines @@
 
   // Scroll past the sticking point, the Y coordinate should now be clamped.
   SetScrollOffsetDelta(scroller_impl, gfx::Vector2dF(0.f, 25.f));
   ExecuteCalculateDrawProperties(root_impl);
   EXPECT_VECTOR2DF_EQ(
       gfx::Vector2dF(20.f, 10.f),
       sticky_pos_impl->ScreenSpaceTransform().To2dTranslation());
 
   // Now the main thread commits the new position of the sticky element.
   scroller->SetScrollOffset(gfx::ScrollOffset(0, 25));
-  sticky_pos->SetPosition(gfx::PointF(0, 15));
-  sticky_pos->SetOffsetForStickyPositionFromMainThread(gfx::Size(0, 5));
+  // Shift the layer by -offset_for_position_sticky.
+  sticky_pos->SetPosition(gfx::PointF(0, 15) - gfx::Vector2dF(0, 5));
   ExecuteCalculateDrawProperties(root.get());
   host()->host_impl()->CreatePendingTree();
   host()->CommitAndCreatePendingTree();
   host()->host_impl()->ActivateSyncTree();
   layer_tree_impl = host()->host_impl()->active_tree();
   root_impl = layer_tree_impl->LayerById(root->id());
   scroller_impl = layer_tree_impl->LayerById(scroller->id());
   sticky_pos_impl = layer_tree_impl->LayerById(sticky_pos->id());
 
   // The element should still be where it was before. We reset the delta to
@@ skipping 3209 matching lines @@
 
   // Check child layer draw properties.
   EXPECT_EQ(gfx::Rect(10, 10), child->visible_layer_rect());
   EXPECT_EQ(gfx::Transform(), child->DrawTransform());
   EXPECT_EQ(gfx::Rect(10, 10), child->clip_rect());
   EXPECT_EQ(gfx::Rect(10, 10), child->drawable_content_rect());
 }
 
 }  // namespace
 }  // namespace cc