Respond to CR.

SignalShareExtension/SAEFailedViewController.swift

@@ -27,10 +27,9 @@ class SAEFailedViewController: UIViewController {
         super.init(nibName: nil, bundle: nil)
     }
 
+    @available(*, unavailable, message:"use other constructor instead.")
     required init?(coder aDecoder: NSCoder) {
-        self.failureTitle = ""
-        self.failureMessage = ""
-        super.init(coder: aDecoder)
+        fatalError("\(#function) is unimplemented.")
     }
 
     override func loadView() {

SignalShareExtension/SAELoadViewController.swift

@@ -24,8 +24,9 @@ class SAELoadViewController: UIViewController {
         super.init(nibName: nil, bundle: nil)
     }
 
+    @available(*, unavailable, message:"use other constructor instead.")
     required init?(coder aDecoder: NSCoder) {
-        super.init(coder: aDecoder)
+        fatalError("\(#function) is unimplemented.")
     }
 
     override func loadView() {

SignalShareExtension/ShareViewController.swift

@@ -49,8 +49,16 @@ public class ShareViewController: UINavigationController, SAELoadViewDelegate, S
             return
         }
 
+        // If we haven't migrated the database file to the shared data
+        // directory we can't load it, and therefore can't init TSSStorageManager,
+        // and therefore don't want to setup most of our machinery (Environment,
+        // most of the singletons, etc.).  We just want to show an error view and
+        // abort.
         isReadyForAppExtensions = OWSPreferences.isReadyForAppExtensions()
         if !isReadyForAppExtensions {
+            // If we don't have TSSStorageManager, we can't consult TSAccountManager
+            // for isRegistered, so we use OWSPreferences which is usually-accurate
+            // copy of that state.
             if (OWSPreferences.isRegistered()) {
                 showNotReadyView()
             } else {