[ios, macos] Corrected polyline equality

Now that annotation classes override -isEqual:, it’s no longer appropriate to rely on -isEqual: or -containsObject: to check for the preexistence of an annotation. Those methods become deep equality tests, which have worse performance. Checking for identity allows the developer to add a polyline and polygon with identical coordinates, title, etc. to the map.

Implemented a missing -[MGLPolyline isEqual:].

Removed outdated comments about -annotationTagForAnnotation: being expensive.

1 files changed, 4 insertions, 0 deletions

diff --git a/platform/darwin/src/MGLPolyline.mm b/platform/darwin/src/MGLPolyline.mm
index 454a1b964b..ae4fbe61de 100644
--- a/platform/darwin/src/MGLPolyline.mm
+++ b/platform/darwin/src/MGLPolyline.mm
@@ -48,6 +48,10 @@
              @"coordinates": self.mgl_coordinates};
 }
 
+- (BOOL)isEqual:(id)other {
+    return self == other || ([other isKindOfClass:[MGLPolyline class]] && [super isEqual:other]);
+}
+
 @end
 
 @interface MGLMultiPolyline ()