cros: Fix avatar not being swapped in login

Bug: 859685
Change-Id: Ibba0f9e17d04e6385b995ed28bf0536507d209e3
Reviewed-on: https://chromium-review.googlesource.com/1124676Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Jacob Dufault <jdufault@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572250}

ash/login/ui/animated_rounded_image_view.cc

@@ -49,8 +49,9 @@ AnimatedRoundedImageView::~AnimatedRoundedImageView() = default;
 void AnimatedRoundedImageView::SetAnimationDecoder(
     std::unique_ptr<AnimationDecoder> decoder) {
   decoder_ = std::move(decoder);
-  // Force a new decode.
+  // Force a new decode and repaint.
   frames_scale_ = NAN;
+  SchedulePaint();
 }
 
 void AnimatedRoundedImageView::SetImage(const gfx::ImageSkia& image) {