Add fiddle demonstrating alpha when used on saveLayer

Change-Id: I4ba2d911a035871512f26201d561d64e9580556b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/277465
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
diff --git a/tools/fiddle/all_examples.cpp b/tools/fiddle/all_examples.cpp
index 0a58be0..8f9967c 100644
--- a/tools/fiddle/all_examples.cpp
+++ b/tools/fiddle/all_examples.cpp
@@ -208,6 +208,7 @@
 #include "../../docs/examples/Canvas_saveLayerPreserveLCDTextRequests.cpp"
 #include "../../docs/examples/Canvas_saveLayer_2.cpp"
 #include "../../docs/examples/Canvas_saveLayer_3.cpp"
+#include "../../docs/examples/Canvas_saveLayer_4.cpp"
 #include "../../docs/examples/Canvas_scale.cpp"
 #include "../../docs/examples/Canvas_setMatrix.cpp"
 #include "../../docs/examples/Canvas_skew.cpp"