iOS: Eliminate fml::scoped_nsobject pointer use (#56295)

Eliminates use of `fml::scoped_nsobject` now that the codebase has been migrated to ARC.

Issue: flutter/flutter#137801

No changes to tests since this patch makes no semantic changes.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: cbracken

shell/gpu/gpu_surface_metal_impeller.h

@@ -9,7 +9,6 @@
 
 #include "flutter/flow/surface.h"
 #include "flutter/fml/macros.h"
-#include "flutter/fml/platform/darwin/scoped_nsobject.h"
 #include "flutter/impeller/display_list/aiks_context.h"
 #include "flutter/impeller/renderer/backend/metal/context_mtl.h"
 #include "flutter/shell/gpu/gpu_surface_metal_delegate.h"

shell/gpu/gpu_surface_metal_skia.mm

@@ -15,7 +15,6 @@
 #include "flutter/common/graphics/persistent_cache.h"
 #include "flutter/fml/make_copyable.h"
 #include "flutter/fml/platform/darwin/cf_utils.h"
-#include "flutter/fml/platform/darwin/scoped_nsobject.h"
 #include "flutter/fml/trace_event.h"
 #include "flutter/shell/gpu/gpu_surface_metal_delegate.h"
 #include "third_party/skia/include/core/SkCanvas.h"

shell/platform/darwin/common/buffer_conversions.mm

@@ -5,7 +5,6 @@
 #import "flutter/shell/platform/darwin/common/buffer_conversions.h"
 
 #include "flutter/fml/macros.h"
-#include "flutter/fml/platform/darwin/scoped_nsobject.h"
 
 static_assert(__has_feature(objc_arc), "ARC must be enabled.");
 

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

@@ -41,7 +41,6 @@ - (instancetype)initWithEnableVMServicePublication:(BOOL)enableVMServicePublicat
 
 #include "flutter/fml/logging.h"
 #include "flutter/fml/message_loop.h"
-#include "flutter/fml/platform/darwin/scoped_nsobject.h"
 #include "flutter/runtime/dart_service_isolate.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterMacros.h"
 

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

@@ -14,7 +14,6 @@
 
 #include "flutter/flow/surface.h"
 #include "flutter/fml/memory/weak_ptr.h"
-#include "flutter/fml/platform/darwin/scoped_nsobject.h"
 #include "flutter/fml/trace_event.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterChannels.h"
 #import "flutter/shell/platform/darwin/ios/framework/Headers/FlutterPlugin.h"

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

@@ -714,7 +714,7 @@ @implementation ForwardingGestureRecognizer {
   // This gesture recognizer retains the `FlutterViewController` until the
   // end of a gesture sequence, that is all the touches in touchesBegan are concluded
   // with |touchesCancelled| or |touchesEnded|.
-  fml::scoped_nsobject<UIViewController<FlutterViewResponder>> _flutterViewController;
+  UIViewController<FlutterViewResponder>* _flutterViewController;
 }
 
 - (instancetype)initWithTarget:(id)target
@@ -741,26 +741,26 @@ - (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
     // At the start of each gesture sequence, we reset the `_flutterViewController`,
     // so that all the touch events in the same sequence are forwarded to the same
     // `_flutterViewController`.
-    _flutterViewController.reset(_platformViewsController->GetFlutterViewController());
+    _flutterViewController = _platformViewsController->GetFlutterViewController();
   }
-  [_flutterViewController.get() touchesBegan:touches withEvent:event];
+  [_flutterViewController touchesBegan:touches withEvent:event];
   _currentTouchPointersCount += touches.count;
 }
 
 - (void)touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
-  [_flutterViewController.get() touchesMoved:touches withEvent:event];
+  [_flutterViewController touchesMoved:touches withEvent:event];
 }
 
 - (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event {
-  [_flutterViewController.get() touchesEnded:touches withEvent:event];
+  [_flutterViewController touchesEnded:touches withEvent:event];
   _currentTouchPointersCount -= touches.count;
   // Touches in one touch sequence are sent to the touchesEnded method separately if different
   // fingers stop touching the screen at different time. So one touchesEnded method triggering does
   // not necessarially mean the touch sequence has ended. We Only set the state to
   // UIGestureRecognizerStateFailed when all the touches in the current touch sequence is ended.
   if (_currentTouchPointersCount == 0) {
     self.state = UIGestureRecognizerStateFailed;
-    _flutterViewController.reset(nil);
+    _flutterViewController = nil;
     [self forceResetStateIfNeeded];
   }
 }
@@ -771,11 +771,11 @@ - (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event {
   // Flutter needs all the cancelled touches to be "cancelled" change types in order to correctly
   // handle gesture sequence.
   // We always override the change type to "cancelled".
-  [_flutterViewController.get() forceTouchesCancelled:touches];
+  [_flutterViewController forceTouchesCancelled:touches];
   _currentTouchPointersCount -= touches.count;
   if (_currentTouchPointersCount == 0) {
     self.state = UIGestureRecognizerStateFailed;
-    _flutterViewController.reset(nil);
+    _flutterViewController = nil;
     [self forceResetStateIfNeeded];
   }
 }

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

@@ -14,7 +14,6 @@
 
 #include "flutter/fml/macros.h"
 #include "flutter/fml/memory/weak_ptr.h"
-#include "flutter/fml/platform/darwin/scoped_nsobject.h"
 #include "flutter/lib/ui/semantics/custom_accessibility_action.h"
 #include "flutter/lib/ui/semantics/semantics_node.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterChannels.h"
@@ -98,10 +97,8 @@ class AccessibilityBridge final : public AccessibilityBridgeIos {
   // (i.e. the status bar or keyboard)
   int32_t last_focused_semantics_object_id_;
 
-  // TODO(cbracken): https://github.com/flutter/flutter/issues/137801
-  // Eliminate use of fml::scoped_* wrappers here.
-  fml::scoped_nsobject<NSMutableDictionary<NSNumber*, SemanticsObject*>> objects_;
-  fml::scoped_nsprotocol<FlutterBasicMessageChannel*> accessibility_channel_;
+  NSMutableDictionary<NSNumber*, SemanticsObject*>* objects_;
+  FlutterBasicMessageChannel* accessibility_channel_;
   int32_t previous_route_id_ = 0;
   std::unordered_map<int32_t, flutter::CustomAccessibilityAction> actions_;
   std::vector<int32_t> previous_routes_;

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

@@ -53,17 +53,17 @@ void PostAccessibilityNotification(UIAccessibilityNotifications notification,
       ios_delegate_(ios_delegate ? std::move(ios_delegate)
                                  : std::make_unique<DefaultIosDelegate>()),
       weak_factory_(this) {
-  accessibility_channel_.reset([[FlutterBasicMessageChannel alloc]
+  accessibility_channel_ = [[FlutterBasicMessageChannel alloc]
          initWithName:@"flutter/accessibility"
       binaryMessenger:platform_view->GetOwnerViewController().engine.binaryMessenger
-                codec:[FlutterStandardMessageCodec sharedInstance]]);
-  [accessibility_channel_.get() setMessageHandler:^(id message, FlutterReply reply) {
+                codec:[FlutterStandardMessageCodec sharedInstance]];
+  [accessibility_channel_ setMessageHandler:^(id message, FlutterReply reply) {
     HandleEvent((NSDictionary*)message);
   }];
 }
 
 AccessibilityBridge::~AccessibilityBridge() {
-  [accessibility_channel_.get() setMessageHandler:nil];
+  [accessibility_channel_ setMessageHandler:nil];
   clearState();
   view_controller_.viewIfLoaded.accessibilityElements = nil;
 }
@@ -74,7 +74,7 @@ void PostAccessibilityNotification(UIAccessibilityNotifications notification,
 
 void AccessibilityBridge::AccessibilityObjectDidBecomeFocused(int32_t id) {
   last_focused_semantics_object_id_ = id;
-  [accessibility_channel_.get() sendMessage:@{@"type" : @"didGainFocus", @"nodeId" : @(id)}];
+  [accessibility_channel_ sendMessage:@{@"type" : @"didGainFocus", @"nodeId" : @(id)}];
 }
 
 void AccessibilityBridge::AccessibilityObjectDidLoseFocus(int32_t id) {
@@ -152,7 +152,7 @@ void PostAccessibilityNotification(UIAccessibilityNotifications notification,
     }
   }
 
-  SemanticsObject* root = objects_.get()[@(kRootNodeId)];
+  SemanticsObject* root = objects_[@(kRootNodeId)];
 
   bool routeChanged = false;
   SemanticsObject* lastAdded = nil;
@@ -196,13 +196,13 @@ void PostAccessibilityNotification(UIAccessibilityNotifications notification,
     view_controller_.viewIfLoaded.accessibilityElements = nil;
   }
 
-  NSMutableArray<NSNumber*>* doomed_uids = [NSMutableArray arrayWithArray:[objects_ allKeys]];
+  NSMutableArray<NSNumber*>* doomed_uids = [NSMutableArray arrayWithArray:objects_.allKeys];
   if (root) {
     VisitObjectsRecursivelyAndRemove(root, doomed_uids);
   }
   [objects_ removeObjectsForKeys:doomed_uids];
 
-  for (SemanticsObject* object in [objects_ allValues]) {
+  for (SemanticsObject* object in objects_.allValues) {
     [object accessibilityBridgeDidFinishUpdate];
   }
 
@@ -217,8 +217,7 @@ void PostAccessibilityNotification(UIAccessibilityNotifications notification,
 
     if (layoutChanged) {
       SemanticsObject* next = FindNextFocusableIfNecessary();
-      SemanticsObject* lastFocused =
-          [objects_.get() objectForKey:@(last_focused_semantics_object_id_)];
+      SemanticsObject* lastFocused = [objects_ objectForKey:@(last_focused_semantics_object_id_)];
       // Only specify the focus item if the new focus is different, avoiding double focuses on the
       // same item. See: https://github.com/flutter/flutter/issues/104176. If there is a route
       // change, we always refocus.
@@ -290,10 +289,10 @@ static bool DidFlagChange(const flutter::SemanticsNode& oldNode,
 
 SemanticsObject* AccessibilityBridge::GetOrCreateObject(int32_t uid,
                                                         flutter::SemanticsNodeUpdates& updates) {
-  SemanticsObject* object = objects_.get()[@(uid)];
+  SemanticsObject* object = objects_[@(uid)];
   if (!object) {
     object = CreateObject(updates[uid], GetWeakPtr());
-    objects_.get()[@(uid)] = object;
+    objects_[@(uid)] = object;
   } else {
     // Existing node case
     auto nodeEntry = updates.find(object.node.id);
@@ -309,7 +308,7 @@ static bool DidFlagChange(const flutter::SemanticsNode& oldNode,
         // SemanticsObject implementation. Instead, we replace it with a new
         // instance.
         SemanticsObject* newSemanticsObject = CreateObject(node, GetWeakPtr());
-        ReplaceSemanticsObject(object, newSemanticsObject, objects_.get());
+        ReplaceSemanticsObject(object, newSemanticsObject, objects_);
         object = newSemanticsObject;
       }
     }
@@ -332,11 +331,11 @@ static bool DidFlagChange(const flutter::SemanticsNode& oldNode,
   }
 
   // Tries to refocus the previous focused semantics object to avoid random jumps.
-  return FindFirstFocusable([objects_.get() objectForKey:@(last_focused_semantics_object_id_)]);
+  return FindFirstFocusable(objects_[@(last_focused_semantics_object_id_)]);
 }
 
 SemanticsObject* AccessibilityBridge::FindFirstFocusable(SemanticsObject* parent) {
-  SemanticsObject* currentObject = parent ?: objects_.get()[@(kRootNodeId)];
+  SemanticsObject* currentObject = parent ?: objects_[@(kRootNodeId)];
   if (!currentObject) {
     return nil;
   }
@@ -360,7 +359,7 @@ static bool DidFlagChange(const flutter::SemanticsNode& oldNode,
     ios_delegate_->PostAccessibilityNotification(UIAccessibilityAnnouncementNotification, message);
   }
   if ([type isEqualToString:@"focus"]) {
-    SemanticsObject* node = objects_.get()[annotatedEvent[@"nodeId"]];
+    SemanticsObject* node = objects_[annotatedEvent[@"nodeId"]];
     ios_delegate_->PostAccessibilityNotification(UIAccessibilityLayoutChangedNotification, node);
   }
 }

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

@@ -11,7 +11,6 @@
 #import <UIKit/UIKit.h>
 
 #include "flow/surface.h"
-#include "fml/platform/darwin/scoped_nsobject.h"
 
 #import "flutter/shell/platform/darwin/ios/ios_context.h"
 
@@ -21,15 +20,15 @@ class IOSSurface;
 
 /// @brief State holder for a Flutter overlay layer.
 struct OverlayLayer {
-  OverlayLayer(const fml::scoped_nsobject<UIView>& overlay_view,
-               const fml::scoped_nsobject<UIView>& overlay_view_wrapper,
+  OverlayLayer(UIView* overlay_view,
+               UIView* overlay_view_wrapper,
                std::unique_ptr<IOSSurface> ios_surface,
                std::unique_ptr<Surface> surface);
 
   ~OverlayLayer() = default;
 
-  fml::scoped_nsobject<UIView> overlay_view;
-  fml::scoped_nsobject<UIView> overlay_view_wrapper;
+  UIView* overlay_view;
+  UIView* overlay_view_wrapper;
   std::unique_ptr<IOSSurface> ios_surface;
   std::unique_ptr<Surface> surface;
 

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

@@ -9,8 +9,8 @@
 
 namespace flutter {
 
-OverlayLayer::OverlayLayer(const fml::scoped_nsobject<UIView>& overlay_view,
-                           const fml::scoped_nsobject<UIView>& overlay_view_wrapper,
+OverlayLayer::OverlayLayer(UIView* overlay_view,
+                           UIView* overlay_view_wrapper,
                            std::unique_ptr<IOSSurface> ios_surface,
                            std::unique_ptr<Surface> surface)
     : overlay_view(overlay_view),
@@ -22,7 +22,6 @@
                                    SkRect rect,
                                    int64_t view_id,
                                    int64_t overlay_id) {
-  UIView* overlay_view_wrapper = this->overlay_view_wrapper.get();
   auto screenScale = [UIScreen mainScreen].scale;
   // Set the size of the overlay view wrapper.
   // This wrapper view masks the overlay view.
@@ -32,7 +31,6 @@
   overlay_view_wrapper.accessibilityIdentifier =
       [NSString stringWithFormat:@"platform_view[%lld].overlay[%lld]", view_id, overlay_id];
 
-  UIView* overlay_view = this->overlay_view.get();
   // Set the size of the overlay view.
   // This size is equal to the device screen size.
   overlay_view.frame = [flutter_view convertRect:flutter_view.bounds toView:overlay_view_wrapper];
@@ -59,32 +57,32 @@
                                    MTLPixelFormat pixel_format) {
   FML_DCHECK([[NSThread currentThread] isMainThread]);
   std::shared_ptr<OverlayLayer> layer;
-  fml::scoped_nsobject<UIView> overlay_view;
-  fml::scoped_nsobject<UIView> overlay_view_wrapper;
+  UIView* overlay_view;
+  UIView* overlay_view_wrapper;
 
   bool impeller_enabled = !!ios_context->GetImpellerContext();
   if (!gr_context && !impeller_enabled) {
-    overlay_view.reset([[FlutterOverlayView alloc] init]);
-    overlay_view_wrapper.reset([[FlutterOverlayView alloc] init]);
+    overlay_view = [[FlutterOverlayView alloc] init];
+    overlay_view_wrapper = [[FlutterOverlayView alloc] init];
 
-    auto ca_layer = fml::scoped_nsobject<CALayer>{[overlay_view.get() layer]};
+    CALayer* ca_layer = overlay_view.layer;
     std::unique_ptr<IOSSurface> ios_surface = IOSSurface::Create(ios_context, ca_layer);
     std::unique_ptr<Surface> surface = ios_surface->CreateGPUSurface();
 
-    layer = std::make_shared<OverlayLayer>(std::move(overlay_view), std::move(overlay_view_wrapper),
+    layer = std::make_shared<OverlayLayer>(overlay_view, overlay_view_wrapper,
                                            std::move(ios_surface), std::move(surface));
   } else {
     CGFloat screenScale = [UIScreen mainScreen].scale;
-    overlay_view.reset([[FlutterOverlayView alloc] initWithContentsScale:screenScale
-                                                             pixelFormat:pixel_format]);
-    overlay_view_wrapper.reset([[FlutterOverlayView alloc] initWithContentsScale:screenScale
-                                                                     pixelFormat:pixel_format]);
+    overlay_view = [[FlutterOverlayView alloc] initWithContentsScale:screenScale
+                                                         pixelFormat:pixel_format];
+    overlay_view_wrapper = [[FlutterOverlayView alloc] initWithContentsScale:screenScale
+                                                                 pixelFormat:pixel_format];
 
-    auto ca_layer = fml::scoped_nsobject<CALayer>{[overlay_view.get() layer]};
+    CALayer* ca_layer = overlay_view.layer;
     std::unique_ptr<IOSSurface> ios_surface = IOSSurface::Create(ios_context, ca_layer);
     std::unique_ptr<Surface> surface = ios_surface->CreateGPUSurface(gr_context);
 
-    layer = std::make_shared<OverlayLayer>(std::move(overlay_view), std::move(overlay_view_wrapper),
+    layer = std::make_shared<OverlayLayer>(overlay_view, overlay_view_wrapper,
                                            std::move(ios_surface), std::move(surface));
     layer->gr_context = gr_context;
   }
@@ -102,8 +100,8 @@
   // |    |    wrapper   |    |  == mask =>  | overlay_view |
   // |    +--------------+    |              +--------------+
   // +------------------------+
-  layer->overlay_view_wrapper.get().clipsToBounds = YES;
-  [layer->overlay_view_wrapper.get() addSubview:layer->overlay_view];
+  layer->overlay_view_wrapper.clipsToBounds = YES;
+  [layer->overlay_view_wrapper addSubview:layer->overlay_view];
 
   layers_.push_back(layer);
 }