Revert "Modernize appearance of "Choose Photo" button in QR code scanner."

This reverts commit 3ac71942a7.

SignalUI/UIKitExtensions/UIButton+SignalUI.swift

@@ -206,41 +206,16 @@ public extension UIButton.Configuration {
         return configuration
     }
 
-    /// Round button that has glass material background on iOS 26+ and no background on older iOS versions.
-    static func round(image: UIImage) -> Self {
-        var configuration: UIButton.Configuration
-        if #available(iOS 26, *) {
-            configuration = .glass()
-        } else {
-            configuration = .plain()
-        }
-        configuration.image = image
-        configuration.baseForegroundColor = .Signal.label
-        configuration.cornerStyle = .capsule
-        configuration.contentInsets = .init(margin: 10) // 44 dp wide and tall if icon is a standard 24x24
-        return configuration
-    }
-
-    /// Round button that has glass material background on iOS 26+ and no background on older iOS versions.
     static func round(themeIcon: ThemeIcon) -> Self {
-        round(image: Theme.iconImage(themeIcon))
-    }
-
-    /// Round button that has glass material background on iOS 26+ and "system chrome" blur on older iOS versions.
-    static func roundMaterial(image: UIImage) -> Self {
         var configuration: UIButton.Configuration
         if #available(iOS 26, *) {
             configuration = .glass()
+            configuration.cornerStyle = .capsule
         } else {
             configuration = .plain()
-
-            var backgroundConfiguration = UIBackgroundConfiguration.clear()
-            backgroundConfiguration.customView = UIVisualEffectView(effect: UIBlurEffect(style: .systemChromeMaterial))
-            configuration.background = backgroundConfiguration
         }
-        configuration.image = image
+        configuration.image = Theme.iconImage(themeIcon)
         configuration.baseForegroundColor = .Signal.label
-        configuration.cornerStyle = .capsule
         configuration.contentInsets = .init(margin: 10) // 44 dp wide and tall if icon is a standard 24x24
         return configuration
     }

SignalUI/ViewControllers/ScanQRCodeViewController.swift

@@ -185,7 +185,7 @@ public class QRCodeScanViewController: OWSViewController {
         fileprivate var backgroundColor: UIColor {
             switch self {
             case .framed:
-                return .Signal.background
+                return .ows_black
             case .unadorned:
                 return .clear
             }
@@ -219,26 +219,39 @@ public class QRCodeScanViewController: OWSViewController {
         return true
     }
 
-    private lazy var uploadPhotoButton = UIButton(
-        configuration: .roundMaterial(image: Theme.iconImage(.buttonPhotoLibrary)),
-        primaryAction: UIAction { [weak self] _ in
+    private lazy var uploadPhotoButton: UIButton = {
+        let button = OWSRoundedButton { [weak self] in
             guard let self else { return }
             self.delegate?.didTapUploadPhotoButton(self)
-        },
-    )
+        }
+
+        button.ows_contentEdgeInsets = UIEdgeInsets(margin: 14)
+
+        // Always use dark theming since it sits over the scan mask.
+        button.setTemplateImageName(
+            Theme.iconName(.buttonPhotoLibrary),
+            tintColor: .ows_white,
+        )
+        button.backgroundColor = .ows_whiteAlpha20
+
+        return button
+    }()
 
     // MARK: - View Lifecycle
 
     override public func viewDidLoad() {
+        AssertIsOnMainThread()
+
         super.viewDidLoad()
 
-        overrideUserInterfaceStyle = .dark
         view.backgroundColor = appearance.backgroundColor
 
         addObservers()
     }
 
     override public func viewDidAppear(_ animated: Bool) {
+        AssertIsOnMainThread()
+
         super.viewDidAppear(animated)
 
         tryToStartScanning()
@@ -253,6 +266,8 @@ public class QRCodeScanViewController: OWSViewController {
     }
 
     override public func viewDidDisappear(_ animated: Bool) {
+        AssertIsOnMainThread()
+
         super.viewDidDisappear(animated)
 
         stopScanning()
@@ -261,6 +276,8 @@ public class QRCodeScanViewController: OWSViewController {
     // MARK: - Notifications
 
     private func addObservers() {
+        AssertIsOnMainThread()
+
         NotificationCenter.default.addObserver(
             self,
             selector: #selector(didEnterBackground),
@@ -289,11 +306,15 @@ public class QRCodeScanViewController: OWSViewController {
 
     @objc
     private func didEnterBackground() {
+        AssertIsOnMainThread()
+
         stopScanning()
     }
 
     @objc
     private func didBecomeActive() {
+        AssertIsOnMainThread()
+
         if self.view.window != nil {
             tryToStartScanning()
         }
@@ -333,6 +354,8 @@ public class QRCodeScanViewController: OWSViewController {
 
     @objc
     public func tryToStartScanning() {
+        AssertIsOnMainThread()
+
         guard nil == scanner else {
             Logger.info("Early return because scanner is not nil")
             return
@@ -380,6 +403,8 @@ public class QRCodeScanViewController: OWSViewController {
     }
 
     private func startScanning() {
+        AssertIsOnMainThread()
+
         guard scanner == nil else {
             owsFailDebug("already scanning")
             return
@@ -803,6 +828,8 @@ private class QRCodeScanner {
     }
 
     func startVideoCapture(initialOrientation: UIInterfaceOrientation) -> Promise<Void> {
+        AssertIsOnMainThread()
+
         guard !Platform.isSimulator else {
             // Trying to actually set up the capture session will fail on a simulator
             // since we don't have actual capture devices. But it's useful to be able