[core] Replace FeatureIndex::collisionTile with a method parameter

This reduces state and simplifies the test added in the prior commit.

src/mbgl/geometry/feature_index.cpp

@@ -59,7 +59,8 @@ void FeatureIndex::query(
  const optional<std::vector<std::string>>& filterLayerIDs,
  const GeometryTileData& geometryTileData,
  const CanonicalTileID& tileID,
- const style::Style& style) const {
+ const style::Style& style,
+ const CollisionTile* collisionTile) const {
 
  mapbox::geometry::box<int16_t> box = mapbox::geometry::envelope(queryGeometry);
 
@@ -154,8 +155,4 @@ void FeatureIndex::addBucketLayerName(const std::string& bucketName, const std::
  bucketLayerIDs[bucketName].push_back(layerID);
 }
 
-void FeatureIndex::setCollisionTile(std::unique_ptr<CollisionTile> collisionTile_) {
- collisionTile = std::move(collisionTile_);
-}
-
 } // namespace mbgl

src/mbgl/geometry/feature_index.hpp

@@ -42,7 +42,8 @@ class FeatureIndex {
  const optional<std::vector<std::string>>& layerIDs,
  const GeometryTileData&,
  const CanonicalTileID&,
- const style::Style&) const;
+ const style::Style&,
+ const CollisionTile*) const;
 
  static optional<GeometryCoordinates> translateQueryGeometry(
  const GeometryCoordinates& queryGeometry,
@@ -53,8 +54,6 @@ class FeatureIndex {
 
  void addBucketLayerName(const std::string& bucketName, const std::string& layerName);
 
- void setCollisionTile(std::unique_ptr<CollisionTile>);
-
 private:
  void addFeature(
  std::unordered_map<std::string, std::vector<Feature>>& result,
@@ -67,7 +66,6 @@ class FeatureIndex {
  const float bearing,
  const float pixelsToTileUnits) const;
 
- std::unique_ptr<CollisionTile> collisionTile;
  GridIndex<IndexedSubfeature> grid;
  unsigned int sortIndex = 0;
 

src/mbgl/text/collision_tile.cpp

@@ -168,7 +168,7 @@ Box CollisionTile::getTreeBox(const Point<float>& anchor, const CollisionBox& bo
  };
 }
 
-std::vector<IndexedSubfeature> CollisionTile::queryRenderedSymbols(const GeometryCoordinates& queryGeometry, float scale) {
+std::vector<IndexedSubfeature> CollisionTile::queryRenderedSymbols(const GeometryCoordinates& queryGeometry, float scale) const {
  std::vector<IndexedSubfeature> result;
  if (queryGeometry.empty() || (tree.empty() && ignoredTree.empty())) {
  return result;

src/mbgl/text/collision_tile.hpp

@@ -42,7 +42,7 @@ class CollisionTile {
  float placeFeature(const CollisionFeature&, bool allowOverlap, bool avoidEdges);
  void insertFeature(CollisionFeature&, float minPlacementScale, bool ignorePlacement);
 
- std::vector<IndexedSubfeature> queryRenderedSymbols(const GeometryCoordinates&, float scale);
+ std::vector<IndexedSubfeature> queryRenderedSymbols(const GeometryCoordinates&, float scale) const;
 
  const PlacementConfig config;
 

src/mbgl/tile/geometry_tile.cpp

@@ -117,7 +117,7 @@ void GeometryTile::onPlacement(PlacementResult result) {
  availableData = DataAvailability::All;
  }
  symbolBuckets = std::move(result.symbolBuckets);
- featureIndex->setCollisionTile(std::move(result.collisionTile));
+ collisionTile = std::move(result.collisionTile);
  observer->onTileChanged(*this);
 }
 
@@ -153,7 +153,8 @@ void GeometryTile::queryRenderedFeatures(
  layerIDs,
  *data,
  id.canonical,
- style);
+ style,
+ collisionTile.get());
 }
 
 } // namespace mbgl

src/mbgl/tile/geometry_tile.hpp

@@ -81,9 +81,11 @@ class GeometryTile : public Tile {
  optional<PlacementConfig> requestedConfig;
 
  std::unordered_map<std::string, std::shared_ptr<Bucket>> nonSymbolBuckets;
- std::unordered_map<std::string, std::shared_ptr<Bucket>> symbolBuckets;
  std::unique_ptr<FeatureIndex> featureIndex;
  std::unique_ptr<const GeometryTileData> data;
+
+ std::unordered_map<std::string, std::shared_ptr<Bucket>> symbolBuckets;
+ std::unique_ptr<CollisionTile> collisionTile;
 };
 
 } // namespace mbgl

test/tile/vector_tile.test.cpp

@@ -62,14 +62,6 @@ TEST(VectorTile, Issue7615) {
  auto symbolBucket = std::make_shared<SymbolBucket>(
  MapMode::Continuous, style::SymbolLayoutProperties::Evaluated(), false, false);
 
- // First onLayout is required so that a non-null FeatureIndex is available.
- tile.onLayout(GeometryTile::LayoutResult {
- {},
- std::make_unique<FeatureIndex>(),
- nullptr,
- 0
- });
-
  // Simulate placement of a symbol layer.
  tile.onPlacement(GeometryTile::PlacementResult {
  {{
@@ -80,7 +72,7 @@ TEST(VectorTile, Issue7615) {
  0
  });
 
- // Second onLayout should not cause the existing symbol bucket to be discarded.
+ // Subsequent onLayout should not cause the existing symbol bucket to be discarded.
  tile.onLayout(GeometryTile::LayoutResult {
  {},
  nullptr,