Fixes Objective-C objects memory leaks (#14326)

Fixes CALayer memory leaks in file FlutterPlatformViews_Internal.mm,FlutterPlatformViews.mm

flutter/flutter#46750

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

@@ -253,7 +253,7 @@ UIView* FlutterPlatformViewsController::ReconstructClipViewsChain(int number_of_
   // If there were not enough existing clip views, add more.
   while (clipIndex < number_of_clips) {
     ChildClippingView* clippingView =
-        [[ChildClippingView alloc] initWithFrame:flutter_view_.get().bounds];
+        [[[ChildClippingView alloc] initWithFrame:flutter_view_.get().bounds] autorelease];
     [clippingView addSubview:head];
     head = clippingView;
     clipIndex++;
@@ -467,8 +467,7 @@ void FlutterPlatformViewsController::EnsureOverlayInitialized(
     if (overlays_.count(overlay_id) != 0) {
       return;
     }
-    fml::scoped_nsobject<FlutterOverlayView> overlay_view(
-        [[[FlutterOverlayView alloc] init] retain]);
+    fml::scoped_nsobject<FlutterOverlayView> overlay_view([[FlutterOverlayView alloc] init]);
     overlay_view.get().frame = flutter_view_.get().bounds;
     overlay_view.get().autoresizingMask =
         (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
@@ -493,7 +492,7 @@ void FlutterPlatformViewsController::EnsureOverlayInitialized(
   }
   auto contentsScale = flutter_view_.get().layer.contentsScale;
   fml::scoped_nsobject<FlutterOverlayView> overlay_view(
-      [[[FlutterOverlayView alloc] initWithContentsScale:contentsScale] retain]);
+      [[FlutterOverlayView alloc] initWithContentsScale:contentsScale]);
   overlay_view.get().frame = flutter_view_.get().bounds;
   overlay_view.get().autoresizingMask =
       (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);

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

@@ -56,11 +56,10 @@ void ResetAnchor(CALayer* layer) {
 
 - (void)clipRect:(const SkRect&)clipSkRect {
   CGRect clipRect = [ChildClippingView getCGRectFromSkRect:clipSkRect];
-  CGPathRef pathRef = CGPathCreateWithRect(clipRect, nil);
-  CAShapeLayer* clip = [[CAShapeLayer alloc] init];
+  fml::CFRef<CGPathRef> pathRef(CGPathCreateWithRect(clipRect, nil));
+  CAShapeLayer* clip = [[[CAShapeLayer alloc] init] autorelease];
   clip.path = pathRef;
   self.layer.mask = clip;
-  CGPathRelease(pathRef);
 }
 
 - (void)clipRRect:(const SkRRect&)clipSkRRect {
@@ -126,7 +125,7 @@ void ResetAnchor(CALayer* layer) {
   // TODO(cyanglaz): iOS does not seem to support hard edge on CAShapeLayer. It clearly stated that
   // the CAShaperLayer will be drawn antialiased. Need to figure out a way to do the hard edge
   // clipping on iOS.
-  CAShapeLayer* clip = [[CAShapeLayer alloc] init];
+  CAShapeLayer* clip = [[[CAShapeLayer alloc] init] autorelease];
   clip.path = pathRef;
   self.layer.mask = clip;
   CGPathRelease(pathRef);
@@ -138,7 +137,7 @@ void ResetAnchor(CALayer* layer) {
   }
   fml::CFRef<CGMutablePathRef> pathRef(CGPathCreateMutable());
   if (path.isEmpty()) {
-    CAShapeLayer* clip = [[CAShapeLayer alloc] init];
+    CAShapeLayer* clip = [[[CAShapeLayer alloc] init] autorelease];
     clip.path = pathRef;
     self.layer.mask = clip;
     return;
@@ -195,7 +194,7 @@ void ResetAnchor(CALayer* layer) {
     verb = iter.next(pts);
   }
 
-  CAShapeLayer* clip = [[CAShapeLayer alloc] init];
+  CAShapeLayer* clip = [[[CAShapeLayer alloc] init] autorelease];
   clip.path = pathRef;
   self.layer.mask = clip;
 }