[ios, macos] Key-value compliance for MGLStyle

Replaced -[MGLMapView style] with a property. Keep the MGLStyle object around for the lifetime of the style.

Bracket changes to layers in willChange and didChange calls. The built-in point annotation layer is added after the style is finished loading but before the map is finished loading. Cause a second wave of change notifications to go out, about both sources and layers. Issue change notifications for style layers when shape annotations are added or removed.

1 files changed, 11 insertions, 4 deletions

diff --git a/platform/ios/src/MGLMapView.h b/platform/ios/src/MGLMapView.h
index e467495a4a..e066387e25 100644
--- a/platform/ios/src/MGLMapView.h
+++ b/platform/ios/src/MGLMapView.h
@@ -118,6 +118,14 @@ IB_DESIGNABLE
 #pragma mark Configuring the Map’s Appearance
 
 /**
+ The style currently displayed in the receiver.
+ 
+ Unlike the `styleURL` property, this property is set to an object that allows
+ you to manipulate every aspect of the style locally.
+ */
+@property (nonatomic, readonly) MGLStyle *style;
+
+/**
  URLs of the styles bundled with the library.
  
  @deprecated Call the relevant class method of `MGLStyle` for the URL of a
@@ -134,6 +142,9 @@ IB_DESIGNABLE
  
  If you set this property to `nil`, the receiver will use the default style
  and this property will automatically be set to that style’s URL.
+ 
+ If you want to modify the current style without replacing it outright, or if
+ you want to introspect individual style attributes, use the `style` property.
  */
 @property (nonatomic, null_resettable) NSURL *styleURL;
 
@@ -1077,10 +1088,6 @@ IB_DESIGNABLE
  */
 - (void)removeOverlays:(NS_ARRAY_OF(id <MGLOverlay>) *)overlays;
 
-#pragma mark - Runtime styling API
-
-- (MGLStyle *)style;
-
 #pragma mark Accessing the Underlying Map Data
 
 /**