[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)

2 files changed, 3 insertions, 1 deletions

diff --git a/src/mbgl/text/quads.cpp b/src/mbgl/text/quads.cpp
index b13a6a71e5..188f88655d 100644
--- a/src/mbgl/text/quads.cpp
+++ b/src/mbgl/text/quads.cpp
@@ -19,6 +19,7 @@ SymbolQuad getIconQuad(const Anchor& anchor,
                        const PositionedIcon& shapedIcon,
                        const GeometryCoordinates& line,
                        const SymbolLayoutProperties::Evaluated& layout,
+                       const float layoutTextSize,
                        const style::SymbolPlacementType placement, 
                        const Shaping& shapedText) {
     auto image = *(shapedIcon.image);
@@ -36,7 +37,7 @@ SymbolQuad getIconQuad(const Anchor& anchor,
     if (layout.get<IconTextFit>() != IconTextFitType::None && shapedText) {
         auto iconWidth = right - left;
         auto iconHeight = bottom - top;
-        auto size = layout.get<TextSize>() / 24.0f;
+        auto size = layoutTextSize / 24.0f;
         auto textLeft = shapedText.left * size;
         auto textRight = shapedText.right * size;
         auto textTop = shapedText.top * size;
diff --git a/src/mbgl/text/quads.hpp b/src/mbgl/text/quads.hpp
index f1529d8829..333000627b 100644
--- a/src/mbgl/text/quads.hpp
+++ b/src/mbgl/text/quads.hpp
@@ -55,6 +55,7 @@ SymbolQuad getIconQuad(const Anchor& anchor,
                        const PositionedIcon& shapedIcon,
                        const GeometryCoordinates& line,
                        const style::SymbolLayoutProperties::Evaluated&,
+                       const float layoutTextSize,
                        style::SymbolPlacementType placement,
                        const Shaping& shapedText);