Merge branch 'release-ios-v3.4.0' into 1ec5-release-ios-v3.4.0-beta.5…

…-master

Also reran make style-code and manually discarded anything related to fill extrusion layers.

include/mbgl/map/map.hpp

@@ -171,6 +171,7 @@ class Map : private util::noncopyable {
     // Add image, bound to the style
     void addImage(const std::string&, std::unique_ptr<const SpriteImage>);
     void removeImage(const std::string&);
+    const SpriteImage* getImage(const std::string&);
 
     // Defaults
     std::string getStyleName() const;

include/mbgl/style/layers/custom_layer.hpp

@@ -7,8 +7,8 @@ namespace style {
 
 /**
  * Initialize any GL state needed by the custom layer. This method is called once, from the
- * rendering thread, at a point when the GL context is active but before rendering for the
- * first time.
+ * main thread, at a point when the GL context is active but before rendering for the first
+ * time.
  *
  * Resources that are acquired in this method must be released in the UninitializeFunction.
  */
@@ -40,7 +40,7 @@ using CustomLayerRenderFunction = void (*)(void* context, const CustomLayerRende
 
 /**
  * Destroy any GL state needed by the custom layer, and deallocate context, if necessary. This
- * method is called once, from the rendering thread, at a point when the GL context is active.
+ * method is called once, from the main thread, at a point when the GL context is active.
  *
  * Note that it may be called even when the InitializeFunction has not been called.
  */