Add EGTests for passwords settings on iOS

ios/chrome/browser/ui/settings/password_details_collection_view_controller.mm

Index: ios/chrome/browser/ui/settings/password_details_collection_view_controller.mm
diff --git a/ios/chrome/browser/ui/settings/password_details_collection_view_controller.mm b/ios/chrome/browser/ui/settings/password_details_collection_view_controller.mm
index 0ab4c0ea05a0d09b3fa6fbe2614b33e209618a65..0cf4b1d63a235e727559e9e668ed620943c093c9 100644
--- a/ios/chrome/browser/ui/settings/password_details_collection_view_controller.mm
+++ b/ios/chrome/browser/ui/settings/password_details_collection_view_controller.mm
@@ -293,6 +293,8 @@ reauthenticationModule:(id<ReauthenticationProtocol>)reauthenticationModule
 }
 
 - (void)showCopyPasswordResultToast:(NSString*)message {
+  // TODO(crbug.com/159166): Route this through some delegate API to be able
+  // to mock it in the unittest, and avoid having an EGTest just for that?
   MDCSnackbarMessage* copyPasswordResultMessage =
       [MDCSnackbarMessage messageWithText:message];
   [MDCSnackbarManager showMessage:copyPasswordResultMessage];
@@ -345,4 +347,11 @@ reauthenticationModule:(id<ReauthenticationProtocol>)reauthenticationModule
   }
 }
 
+#pragma mark - ForTesting
+
+- (void)setReauthenticationModule:
+    (id<ReauthenticationProtocol>)reauthenticationModule {
+  _weakReauthenticationModule = reauthenticationModule;
+}
+
 @end