[core] Add expression filter support (#11251)

* WIP

* WIP

* WIP

* Remove Filter::operator()(const Feature&)

* WIP

* WIP

* WIP

* WIP

* Hook up expression filter evaluator

* Replace `shared_ptr` with &reference

* Fill in implementation of `void operator()(const ExpressionFilter&)`

* Fix failing tests

* Switch back to a shared_ptr per chat with @anandthakker

* Fix benchmark compilation

* Shot in the dark to fix CI

* Shot in the dark to fix CI (part 2)

* Shot in the dark to fix CI (part 3)

* In src/mbgl/style/conversion/filter.cpp, add a port of isExpressionFilter and use it to decide in Converter<Filter>::operator() whether to parse the incoming JSON as an ExpressionFilter or one of the legacy filter types

* Remove bool Filter::operator()(const GeometryTileFeature&) const

*  Ensure the map zoom is passed into filtering operations wherever applicable

* Add expression filter tests

* Addressed PR feedback

* Implement `NSPredicate *operator()(mbgl::style::ExpressionFilter filter)`

* Fix formatting& nit

2 files changed, 4 insertions, 7 deletions

diff --git a/benchmark/fixtures/api/cache.db b/benchmark/fixtures/api/cache.db
index 6a1d60421f..10452b2714 100644
--- a/benchmark/fixtures/api/cache.db
+++ b/benchmark/fixtures/api/cache.db
diff --git a/benchmark/parse/filter.benchmark.cpp b/benchmark/parse/filter.benchmark.cpp
index 4984668400..e4cf635256 100644
--- a/benchmark/parse/filter.benchmark.cpp
+++ b/benchmark/parse/filter.benchmark.cpp
@@ -6,6 +6,7 @@
 #include <mbgl/style/conversion/json.hpp>
 #include <mbgl/style/conversion/filter.hpp>
 #include <mbgl/tile/geometry_tile_data.hpp>
+#include <mbgl/benchmark/stub_geometry_tile_feature.hpp>
 
 using namespace mbgl;
 
@@ -22,15 +23,11 @@ static void Parse_Filter(benchmark::State& state) {
 
 static void Parse_EvaluateFilter(benchmark::State& state) {
     const style::Filter filter = parse(R"FILTER(["==", "foo", "bar"])FILTER");
-    const PropertyMap properties = { { "foo", std::string("bar") } };
+    const StubGeometryTileFeature feature = { {}, FeatureType::Unknown , {},  {{ "foo", std::string("bar") }} };
+    const style::expression::EvaluationContext context = { &feature };
 
     while (state.KeepRunning()) {
-        filter(FeatureType::Unknown, {}, [&] (const std::string& key) -> optional<Value> {
-            auto it = properties.find(key);
-            if (it == properties.end())
-                return {};
-            return it->second;
-        });
+        filter(context);
     }
 }