Refactor Semantics in preparation for ARC migration

shell/platform/darwin/ios/framework/Source/FlutterSemanticsScrollView.mm

@@ -25,81 +25,81 @@ - (UIView*)hitTest:(CGPoint)point withEvent:(UIEvent*)event {
 // UIScrollView class, the base class.
 
 - (BOOL)isAccessibilityElement {
- if (![_semanticsObject isAccessibilityBridgeAlive]) {
+ if (![self.semanticsObject isAccessibilityBridgeAlive]) {
  return NO;
  }
 
- if ([_semanticsObject isAccessibilityElement]) {
+ if (self.semanticsObject.isAccessibilityElement) {
  return YES;
  }
  if (self.contentSize.width > self.frame.size.width ||
  self.contentSize.height > self.frame.size.height) {
  // In SwitchControl or VoiceControl, the isAccessibilityElement must return YES
  // in order to use scroll actions.
- return ![_semanticsObject bridge]->isVoiceOverRunning();
+ return ![self.semanticsObject bridge]->isVoiceOverRunning();
  } else {
  return NO;
  }
 }
 
 - (NSString*)accessibilityLabel {
- return [_semanticsObject accessibilityLabel];
+ return self.semanticsObject.accessibilityLabel;
 }
 
 - (NSAttributedString*)accessibilityAttributedLabel {
- return [_semanticsObject accessibilityAttributedLabel];
+ return self.semanticsObject.accessibilityAttributedLabel;
 }
 
 - (NSString*)accessibilityValue {
- return [_semanticsObject accessibilityValue];
+ return self.semanticsObject.accessibilityValue;
 }
 
 - (NSAttributedString*)accessibilityAttributedValue {
- return [_semanticsObject accessibilityAttributedValue];
+ return self.semanticsObject.accessibilityAttributedValue;
 }
 
 - (NSString*)accessibilityHint {
- return [_semanticsObject accessibilityHint];
+ return self.semanticsObject.accessibilityHint;
 }
 
 - (NSAttributedString*)accessibilityAttributedHint {
- return [_semanticsObject accessibilityAttributedHint];
+ return self.semanticsObject.accessibilityAttributedHint;
 }
 
 - (BOOL)accessibilityActivate {
- return [_semanticsObject accessibilityActivate];
+ return [self.semanticsObject accessibilityActivate];
 }
 
 - (void)accessibilityIncrement {
- [_semanticsObject accessibilityIncrement];
+ [self.semanticsObject accessibilityIncrement];
 }
 
 - (void)accessibilityDecrement {
- [_semanticsObject accessibilityDecrement];
+ [self.semanticsObject accessibilityDecrement];
 }
 
 - (BOOL)accessibilityScroll:(UIAccessibilityScrollDirection)direction {
- return [_semanticsObject accessibilityScroll:direction];
+ return [self.semanticsObject accessibilityScroll:direction];
 }
 
 - (BOOL)accessibilityPerformEscape {
- return [_semanticsObject accessibilityPerformEscape];
+ return [self.semanticsObject accessibilityPerformEscape];
 }
 
 - (void)accessibilityElementDidBecomeFocused {
- [_semanticsObject accessibilityElementDidBecomeFocused];
+ [self.semanticsObject accessibilityElementDidBecomeFocused];
 }
 
 - (void)accessibilityElementDidLoseFocus {
- [_semanticsObject accessibilityElementDidLoseFocus];
+ [self.semanticsObject accessibilityElementDidLoseFocus];
 }
 
 - (id)accessibilityContainer {
- return [_semanticsObject accessibilityContainer];
+ return self.semanticsObject.accessibilityContainer;
 }
 
 - (NSInteger)accessibilityElementCount {
- return [[_semanticsObject children] count];
+ return self.semanticsObject.children.count;
 }
 
 @end

shell/platform/darwin/ios/framework/Source/SemanticsObject.h

@@ -38,7 +38,7 @@ constexpr float kScrollExtentMaxForInf = 1000;
  * The parent of this node in the node tree. Will be nil for the root node and
  * during transient state changes.
  */
-@property(nonatomic, assign) SemanticsObject* parent;
+@property(nonatomic, assign, readonly) SemanticsObject* parent;
 
 /**
  * The accessibility bridge that this semantics object is attached to. This
@@ -64,13 +64,13 @@ constexpr float kScrollExtentMaxForInf = 1000;
  * Direct children of this semantics object. Each child's `parent` property must
  * be equal to this object.
  */
-@property(nonatomic, strong) NSArray<SemanticsObject*>* children;
+@property(nonatomic, copy) NSArray<SemanticsObject*>* children;
 
 /**
  * Direct children of this semantics object in hit test order. Each child's `parent` property
  * must be equal to this object.
  */
-@property(nonatomic, strong) NSArray<SemanticsObject*>* childrenInHitTestOrder;
+@property(nonatomic, copy) NSArray<SemanticsObject*>* childrenInHitTestOrder;
 
 /**
  * The UIAccessibility that represents this object.
@@ -231,7 +231,7 @@ constexpr float kScrollExtentMaxForInf = 1000;
  bridge:(fml::WeakPtr<flutter::AccessibilityBridgeIos>)bridge
  NS_DESIGNATED_INITIALIZER;
 
-@property(nonatomic, weak) SemanticsObject* semanticsObject;
+@property(nonatomic, assign) SemanticsObject* semanticsObject;
 
 @end