[skottie] Re-enable inval tracking in viewer

This was disabled accidentally at some point.

TBR=

Change-Id: I7d537e519aca983ce2f9b5428820ba87f8113789
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/306539
Reviewed-by: Florin Malita <fmalita@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>

Author: fmalita

tools/viewer/SkottieSlide.cpp

@@ -217,7 +217,8 @@ bool SkottieSlide::animate(double nanos) {
             fCurrentFrame = std::trunc(fCurrentFrame * fps_scale) / fps_scale;
         }
 
-        fAnimation->seekFrame(fCurrentFrame);
+        fAnimation->seekFrame(fCurrentFrame, fShowAnimationInval ? &fInvalController
+                                                                 : nullptr);
     }
     return true;
 }