[core] Add DDS support for {text,icon}-size (#8593)

* Update gl-js and generate style code

* Factor out packUint8Pair() helper function

* Draft implementation of DDS for {text,icon}-size

Ports https://github.com/mapbox/mapbox-gl-js/pull/4455

* Fix text-size/composite-function-line-placement test

* Refactor to PaintPropertyBinders-like strategy

* Dedupe gl::Program construction

* Use exponential function base for interpolation

* Dedupe coveringZoomStops method

* Fixup tests

* Fix CI errors (hidden within #if block)

1 files changed, 13 insertions, 4 deletions

diff --git a/src/mbgl/layout/symbol_layout.hpp b/src/mbgl/layout/symbol_layout.hpp
index d79ccb3273..4ec84f0f58 100644
--- a/src/mbgl/layout/symbol_layout.hpp
+++ b/src/mbgl/layout/symbol_layout.hpp
@@ -6,6 +6,7 @@
 #include <mbgl/layout/symbol_instance.hpp>
 #include <mbgl/text/bidi.hpp>
 #include <mbgl/style/layers/symbol_layer_impl.hpp>
+#include <mbgl/programs/symbol_program.hpp>
 
 #include <memory>
 #include <map>
@@ -64,9 +65,15 @@ private:
 
     // Adds placed items to the buffer.
     template <typename Buffer>
-    void addSymbol(Buffer&, const SymbolQuad&, float scale,
-                    const bool keepUpright, const style::SymbolPlacementType, const float placementAngle,
-                    WritingModeType writingModes);
+    void addSymbol(Buffer&,
+                   SymbolSizeBinder& sizeBinder,
+                   const SymbolQuad&,
+                   const SymbolFeature& feature,
+                   float scale,
+                   const bool keepUpright,
+                   const style::SymbolPlacementType,
+                   const float placementAngle,
+                   WritingModeType writingModes);
 
     const std::string sourceLayerName;
     const std::string bucketName;
@@ -75,7 +82,6 @@ private:
     const MapMode mode;
 
     style::SymbolLayoutProperties::PossiblyEvaluated layout;
-    float textMaxSize;
     
     uintptr_t spriteAtlasMapIndex; // Actually a pointer to the SpriteAtlas for this symbol's layer, but don't use it from worker threads!
 
@@ -84,6 +90,9 @@ private:
 
     bool sdfIcons = false;
     bool iconsNeedLinear = false;
+    
+    style::TextSize::UnevaluatedType textSize;
+    style::IconSize::UnevaluatedType iconSize;
 
     std::vector<SymbolInstance> symbolInstances;
     std::vector<SymbolFeature> features;