- upgrade

Example/Pods/FBSnapshotTestCase/FBSnapshotTestCase/FBSnapshotTestController.h

@@ -28,6 +28,21 @@ extern NSString *const FBSnapshotTestControllerErrorDomain;
  */
 extern NSString *const FBReferenceImageFilePathKey;
 
+/**
+ Errors returned by the methods of FBSnapshotTestController sometimes contain this key in the `userInfo` dictionary.
+ */
+extern NSString *const FBReferenceImageKey;
+
+/**
+ Errors returned by the methods of FBSnapshotTestController sometimes contain this key in the `userInfo` dictionary.
+ */
+extern NSString *const FBCapturedImageKey;
+
+/**
+ Errors returned by the methods of FBSnapshotTestController sometimes contain this key in the `userInfo` dictionary.
+ */
+extern NSString *const FBDiffedImageKey;
+
 /**
  Provides the heavy-lifting for FBSnapshotTestCase. It loads and saves images, along with performing the actual pixel-
  by-pixel comparison of images.