[Fabric] Convert UIActivityIndicatorView to RCTActivityIndicatorView shim (#1528)

* [Fabric] Replace UIKit with RCTUIKit

* [Fabric] Convert UIActivityIndicatorView to RCTActivityIndicatorView shim

* Add macOS tags

* Shim RCTUIActivityIndicatorView instead of using RCTActivityIndicatorView

* Shim correct NSProgressIndicator

* Move RCTUIActivityIndicatorView below other defs for easier merges

Co-authored-by: Shawn Dempsey <shawndempsey@fb.com>
Co-authored-by: lyzhan7 <78454019+lyzhan7@users.noreply.github.com>

React/Base/RCTUIKit.h

@@ -480,7 +480,7 @@ NS_INLINE CGRect CGRectValue(NSValue *value)
 #else
 @interface RCTUISlider : NSSlider
 @end
-#endif // ]TODO(macOS GH#774)
+#endif // ]TODO(macOS GH#774)n
 
 // RCTUILabel
 
@@ -499,3 +499,21 @@ NS_INLINE CGRect CGRectValue(NSValue *value)
 @interface RCTUISwitch : NSSwitch
 @end
 #endif // ]TODO(macOS GH#774)
+
+// RCTUIActivityIndicatorView
+
+#if !TARGET_OS_OSX // [TODO(macOS GH#774)
+#define RCTUIActivityIndicatorView UIActivityIndicatorView
+#else
+@interface RCTUIActivityIndicatorView : NSProgressIndicator
+
+@property (nonatomic, assign) UIActivityIndicatorViewStyle activityIndicatorViewStyle;
+@property (nonatomic, assign) BOOL hidesWhenStopped;
+@property (nullable, readwrite, nonatomic, strong) RCTUIColor *color;
+@property (nonatomic, readonly, getter=isAnimating) BOOL animating;
+
+- (void)startAnimating;
+- (void)stopAnimating;
+
+@end
+#endif // ]TODO(macOS GH#774)

React/Fabric/Mounting/ComponentViews/ActivityIndicator/RCTActivityIndicatorViewComponentView.mm

@@ -8,6 +8,7 @@
 #import "RCTActivityIndicatorViewComponentView.h"
 
 #import <React/RCTConversions.h>
+#import <React/RCTActivityIndicatorView.h> // TODO(macOS GH#774)
 
 #import <react/renderer/components/rncore/ComponentDescriptors.h>
 #import <react/renderer/components/rncore/EventEmitters.h>
@@ -28,7 +29,7 @@ static UIActivityIndicatorViewStyle convertActivityIndicatorViewStyle(const Acti
 }
 
 @implementation RCTActivityIndicatorViewComponentView {
-  UIActivityIndicatorView *_activityIndicatorView;
+  RCTUIActivityIndicatorView *_activityIndicatorView; // TODO(macOS GH#774)
 }
 
 #pragma mark - RCTComponentViewProtocol
@@ -44,7 +45,7 @@ static UIActivityIndicatorViewStyle convertActivityIndicatorViewStyle(const Acti
     static const auto defaultProps = std::make_shared<const ActivityIndicatorViewProps>();
     _props = defaultProps;
 
-    _activityIndicatorView = [[UIActivityIndicatorView alloc] initWithFrame:self.bounds];
+    _activityIndicatorView = [[RCTUIActivityIndicatorView alloc] initWithFrame:self.bounds]; // TODO(macOS GH#774)
     _activityIndicatorView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
 
     if (defaultProps->animating) {