[core] De-mutex GlyphAtlas and SpriteAtlas

 - Expose glyph and icon information to workers via message interface.
 - Glyph/SpriteAtlas track which tiles have outstanding requests
    and send messages to them when glyphs/icons become available.
 - Remove obsolete "updateSymbolDependentTiles" pathway
 - Symbol preparation for a tile now depends on all glyphs becoming
    available before it can start.
 - Start tracking individual icons needed for a tile, although we don't
    do anything with the information yet.
 - Introduce typedef for GlyphID

1 files changed, 4 insertions, 2 deletions

diff --git a/src/mbgl/text/glyph_pbf.hpp b/src/mbgl/text/glyph_pbf.hpp
index 7412ebe411..d5b89cd107 100644
--- a/src/mbgl/text/glyph_pbf.hpp
+++ b/src/mbgl/text/glyph_pbf.hpp
@@ -8,10 +8,12 @@
 #include <functional>
 #include <string>
 #include <memory>
+#include <unordered_map>
 
 namespace mbgl {
 
 class GlyphAtlas;
+class GlyphRequestor;
 class GlyphAtlasObserver;
 class AsyncRequest;
 class FileSource;
@@ -29,10 +31,10 @@ public:
         return parsed;
     }
 
-private:
-    std::atomic<bool> parsed;
+    bool parsed;
     std::unique_ptr<AsyncRequest> req;
     GlyphAtlasObserver* observer = nullptr;
+    std::unordered_map<GlyphRequestor*, std::shared_ptr<GlyphDependencies>> requestors;
 };
 
 } // namespace mbgl