Enable voice over mode on device while running in accessibility exploration mode

Summary:
All the FoA have different logic depending on whether device is running in  VoiceOver mode or not. This results in incorrect accessibility being reported through the Flipper plugin.

For example on Instagram we fetch the image descriptions, in Facebook app we group individual elements into the accessibility groups to simplify traversing the screen

This tells device that it is in a voice over mode while inspecting accessibility mode is on meaning that it will be the closest approximation to the

Reviewed By: nscoding

Differential Revision: D49579241

fbshipit-source-id: f3be9057007ee6eefbe3b448f0f97c1fcd2c8f46

iOS/Plugins/FlipperKitUIDebuggerPlugin/FlipperKitUIDebuggerPlugin/Observer/UIDTreeObserver.m

@@ -33,6 +33,15 @@
   [self processNode:node withSnapshot:false withContext:context];
 }
 
+- (void)setTraversalMode:(UIDTraversalMode)traversalMode {
+  if (_traversalMode == traversalMode) {
+    return;
+  }
+  _traversalMode = traversalMode;
+  [UIDAllyTraversal setVoiceOverServiceEnabled:traversalMode ==
+                    UIDTraversalModeAccessibilityHierarchy];
+}
+
 - (void)processNode:(id)node
        withSnapshot:(BOOL)snapshot
         withContext:(UIDContext*)context {

iOS/Plugins/FlipperKitUIDebuggerPlugin/FlipperKitUIDebuggerPlugin/Traversal/UIDAllyTraversal.h

@@ -17,6 +17,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface UIDAllyTraversal : NSObject
 
++ (void)setVoiceOverServiceEnabled:(BOOL)enabled;
+
 @property(nonatomic, class, readonly, getter=isSupported) BOOL supported;
 
 - (instancetype)initWithDescriptorRegister:

iOS/Plugins/FlipperKitUIDebuggerPlugin/FlipperKitUIDebuggerPlugin/Traversal/UIDAllyTraversal.m

@@ -8,6 +8,7 @@
 #if FB_SONARKIT_ENABLED
 
 #import "UIDAllyTraversal.h"
+#import <dlfcn.h>
 #import "UIDDescriptorRegister.h"
 #import "UIDMetadataRegister.h"
 #import "UIDNode.h"
@@ -34,6 +35,12 @@
              (_accessibilityLeafDescendantsWithOptions:)];
 }
 
++ (void)setVoiceOverServiceEnabled:(BOOL)enabled {
+  if (self.isSupported) {
+    _setVoiceOver(enabled);
+  }
+}
+
 - (instancetype)initWithDescriptorRegister:
     (UIDDescriptorRegister*)descriptorRegister {
   self = [super init];
@@ -114,6 +121,25 @@ static BOOL _loadAccessibilityFramework(void) {
   return isAccessibilityFrameworkLoaded;
 }
 
+static void _setVoiceOver(BOOL enabled) {
+  NSString* const accessibilityUtilitiesPath =
+      [[NSBundle bundleForClass:UIApplication.class]
+              .bundleURL.URLByDeletingLastPathComponent
+              .URLByDeletingLastPathComponent
+          URLByAppendingPathComponent:
+              @"PrivateFrameworks/AccessibilityUtilities.framework/AccessibilityUtilities"]
+          .relativePath;
+  void* handler = dlopen(
+      [accessibilityUtilitiesPath cStringUsingEncoding:NSUTF8StringEncoding],
+      RTLD_NOW);
+  if (!handler) {
+    return;
+  }
+  void (*_AXSVoiceOverTouchSetEnabled)(BOOL) =
+      dlsym(handler, "_AXSVoiceOverTouchSetEnabled");
+  _AXSVoiceOverTouchSetEnabled(enabled);
+}
+
 static NSString* _nameForNode(NSObject* node) {
   NSMutableArray* const parts = [NSMutableArray new];
   if (node.accessibilityLabel.length > 0) {