Handle nested position:sticky elements correctly (compositor)

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 ed9c242b68386d43fd351d9226f4b8c73677186b..1924e964a4ce535d01755ad98d562b64069b3444 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -7074,11 +7074,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionTop) {
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_top = true;
   sticky_position.top_offset = 10.0f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(10, 20);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(10, 20);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(10, 20, 10, 10);
+      gfx::RectF(10, 20, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(0, 0, 50, 50);
+      gfx::RectF(0, 0, 50, 50);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7143,15 +7143,18 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionTopScrollParent) {
   host()->SetRootLayer(root);
   scroller->SetScrollClipLayerId(container->id());
 
+  // The sticky layer has already been scrolled on the main thread side, and has
+  // stuck. This test then checks that further changes from cc-only scrolling
+  // are handled correctly.
   LayerStickyPositionConstraint sticky_position;
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_top = true;
   sticky_position.top_offset = 10.0f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(10, 20);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(10, 20);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(10, 20, 10, 10);
+      gfx::RectF(10, 20, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(0, 0, 50, 50);
+      gfx::RectF(0, 0, 50, 50);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(200, 200));
@@ -7220,11 +7223,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionSubpixelScroll) {
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_bottom = true;
   sticky_position.bottom_offset = 10.0f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(0, 200);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(0, 200);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(0, 200, 10, 10);
+      gfx::RectF(0, 200, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(0, 0, 100, 500);
+      gfx::RectF(0, 0, 100, 500);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7266,11 +7269,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionBottom) {
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_bottom = true;
   sticky_position.bottom_offset = 10.0f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(0, 150);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(0, 150);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(0, 150, 10, 10);
+      gfx::RectF(0, 150, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(0, 100, 50, 50);
+      gfx::RectF(0, 100, 50, 50);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7335,11 +7338,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionBottomInnerViewportDelta) {
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_bottom = true;
   sticky_position.bottom_offset = 10.0f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(0, 70);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(0, 70);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(0, 70, 10, 10);
+      gfx::RectF(0, 70, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(0, 60, 100, 100);
+      gfx::RectF(0, 60, 100, 100);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7408,11 +7411,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionBottomOuterViewportDelta) {
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_bottom = true;
   sticky_position.bottom_offset = 10.0f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(0, 70);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(0, 70);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(0, 70, 10, 10);
+      gfx::RectF(0, 70, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(0, 60, 100, 100);
+      gfx::RectF(0, 60, 100, 100);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7485,11 +7488,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionLeftRight) {
   sticky_position.is_anchored_right = true;
   sticky_position.left_offset = 10.f;
   sticky_position.right_offset = 10.f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(145, 0);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(145, 0);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(145, 0, 10, 10);
+      gfx::RectF(145, 0, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(100, 0, 100, 100);
+      gfx::RectF(100, 0, 100, 100);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7588,11 +7591,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionMainThreadUpdates) {
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_top = true;
   sticky_position.top_offset = 10.0f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(10, 20);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(10, 20);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(10, 20, 10, 10);
+      gfx::RectF(10, 20, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(0, 0, 50, 50);
+      gfx::RectF(0, 0, 50, 50);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7683,11 +7686,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionCompositedContainer) {
   // The sticky position layer is only offset by (0, 10) from its parent
   // layer, this position is used to determine the offset applied by the main
   // thread.
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(0, 10);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(0, 10);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(20, 30, 10, 10);
+      gfx::RectF(20, 30, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(20, 20, 30, 30);
+      gfx::RectF(20, 20, 30, 30);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7783,11 +7786,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionScaledStickyBox) {
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_top = true;
   sticky_position.top_offset = 0.0f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(0, 20);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(0, 20);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(0, 20, 10, 10);
+      gfx::RectF(0, 20, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(0, 0, 50, 50);
+      gfx::RectF(0, 0, 50, 50);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7862,11 +7865,11 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionScaledContainer) {
   sticky_position.is_sticky = true;
   sticky_position.is_anchored_top = true;
   sticky_position.top_offset = 0.0f;
-  sticky_position.parent_relative_sticky_box_offset = gfx::Point(0, 20);
+  sticky_position.parent_relative_sticky_box_offset = gfx::PointF(0, 20);
   sticky_position.scroll_container_relative_sticky_box_rect =
-      gfx::Rect(0, 20, 10, 10);
+      gfx::RectF(0, 20, 10, 10);
   sticky_position.scroll_container_relative_containing_block_rect =
-      gfx::Rect(0, 0, 50, 50);
+      gfx::RectF(0, 0, 50, 50);
   sticky_pos->SetStickyPositionConstraint(sticky_position);
 
   root->SetBounds(gfx::Size(100, 100));
@@ -7920,6 +7923,106 @@ TEST_F(LayerTreeHostCommonTest, StickyPositionScaledContainer) {
       sticky_pos_impl->ScreenSpaceTransform().To2dTranslation());
 }
 
+TEST_F(LayerTreeHostCommonTest, StickyPositionNested) {
+  scoped_refptr<Layer> root = Layer::Create();
+  scoped_refptr<Layer> container = Layer::Create();
+  scoped_refptr<Layer> scroller = Layer::Create();
+  scoped_refptr<Layer> outer_sticky = Layer::Create();
+  scoped_refptr<Layer> inner_sticky = Layer::Create();
+
+  root->AddChild(container);
+  container->AddChild(scroller);
+  scroller->AddChild(outer_sticky);
+  outer_sticky->AddChild(inner_sticky);
+  host()->SetRootLayer(root);
+  scroller->SetScrollClipLayerId(container->id());
+
+  root->SetBounds(gfx::Size(100, 100));
+  container->SetBounds(gfx::Size(100, 100));
+  scroller->SetBounds(gfx::Size(100, 1000));
+  outer_sticky->SetBounds(gfx::Size(10, 50));
+  outer_sticky->SetPosition(gfx::PointF(0, 50));
+  inner_sticky->SetBounds(gfx::Size(10, 10));
+  inner_sticky->SetPosition(gfx::PointF(0, 0));
+
+  LayerStickyPositionConstraint outer_sticky_pos;
+  outer_sticky_pos.is_sticky = true;
+  outer_sticky_pos.is_anchored_top = true;
+  outer_sticky_pos.top_offset = 10.0f;
+  outer_sticky_pos.parent_relative_sticky_box_offset = gfx::PointF(0, 50);
+  outer_sticky_pos.scroll_container_relative_sticky_box_rect =
+      gfx::RectF(0, 50, 10, 50);
+  outer_sticky_pos.scroll_container_relative_containing_block_rect =
+      gfx::RectF(0, 0, 50, 400);
+  outer_sticky->SetStickyPositionConstraint(outer_sticky_pos);
+
+  LayerStickyPositionConstraint inner_sticky_pos;
+  inner_sticky_pos.is_sticky = true;
+  inner_sticky_pos.is_anchored_top = true;
+  inner_sticky_pos.top_offset = 25.0f;
+  inner_sticky_pos.parent_relative_sticky_box_offset = gfx::PointF(0, 0);
+  inner_sticky_pos.scroll_container_relative_sticky_box_rect =
+      gfx::RectF(0, 50, 10, 10);
+  inner_sticky_pos.scroll_container_relative_containing_block_rect =
+      gfx::RectF(0, 50, 10, 50);
+  inner_sticky_pos.nearest_layer_shifting_containing_block = outer_sticky->id();
+  inner_sticky->SetStickyPositionConstraint(inner_sticky_pos);
+
+  ExecuteCalculateDrawProperties(root.get());
+  host()->host_impl()->CreatePendingTree();
+  host()->CommitAndCreatePendingTree();
+  host()->host_impl()->ActivateSyncTree();
+  LayerTreeImpl* layer_tree_impl = host()->host_impl()->active_tree();
+
+  LayerImpl* root_impl = layer_tree_impl->LayerById(root->id());
+  LayerImpl* scroller_impl = layer_tree_impl->LayerById(scroller->id());
+  LayerImpl* outer_sticky_impl = layer_tree_impl->LayerById(outer_sticky->id());
+  LayerImpl* inner_sticky_impl = layer_tree_impl->LayerById(inner_sticky->id());
+
+  ExecuteCalculateDrawProperties(root_impl);
+
+  // Before any scrolling is done, the sticky elements should still be at their
+  // original positions.
+  EXPECT_VECTOR2DF_EQ(
+      gfx::Vector2dF(0.f, 50.f),
+      outer_sticky_impl->ScreenSpaceTransform().To2dTranslation());
+  EXPECT_VECTOR2DF_EQ(
+      gfx::Vector2dF(0.f, 50.f),
+      inner_sticky_impl->ScreenSpaceTransform().To2dTranslation());
+
+  // Scroll less than the sticking point. Both sticky elements should move with
+  // scroll as we haven't gotten to the sticky item locations yet.
+  SetScrollOffsetDelta(scroller_impl, gfx::Vector2dF(0.f, 5.f));
+  ExecuteCalculateDrawProperties(root_impl);
+  EXPECT_VECTOR2DF_EQ(
+      gfx::Vector2dF(0.f, 45.f),
+      outer_sticky_impl->ScreenSpaceTransform().To2dTranslation());
+  EXPECT_VECTOR2DF_EQ(
+      gfx::Vector2dF(0.f, 45.f),
+      inner_sticky_impl->ScreenSpaceTransform().To2dTranslation());
+
+  // Scroll such that the inner sticky should stick, but the outer one should
+  // keep going as it hasnt reached its position yet.

[ajuma, 2017/03/17 23:59:52]

hasn't

[smcgruer, 2017/03/20 13:36:29]

Done.

+  SetScrollOffsetDelta(scroller_impl, gfx::Vector2dF(0.f, 30.f));
+  ExecuteCalculateDrawProperties(root_impl);
+  EXPECT_VECTOR2DF_EQ(
+      gfx::Vector2dF(0.f, 20.f),
+      outer_sticky_impl->ScreenSpaceTransform().To2dTranslation());
+  EXPECT_VECTOR2DF_EQ(
+      gfx::Vector2dF(0.f, 25.f),
+      inner_sticky_impl->ScreenSpaceTransform().To2dTranslation());
+
+  // Keep going, both should stick.
+  SetScrollOffsetDelta(scroller_impl, gfx::Vector2dF(0.f, 100.f));
+  ExecuteCalculateDrawProperties(root_impl);
+  EXPECT_VECTOR2DF_EQ(
+      gfx::Vector2dF(0.f, 10.f),
+      outer_sticky_impl->ScreenSpaceTransform().To2dTranslation());
+  EXPECT_VECTOR2DF_EQ(
+      gfx::Vector2dF(0.f, 25.f),
+      inner_sticky_impl->ScreenSpaceTransform().To2dTranslation());
+}
+
 TEST_F(LayerTreeHostCommonTest, NonFlatContainerForFixedPosLayer) {
   scoped_refptr<Layer> root = Layer::Create();
   scoped_refptr<Layer> container = Layer::Create();