Replace deprecated scoped_array<T> with scoped_ptr<T[]>

BUG=chromium:338610
TEST=`emerge-link touch_noise_filter`

Change-Id: I81bb9f6f32639f5fb771bfb4193b6632c6b552ea
Reviewed-on: https://chromium-review.googlesource.com/184057
Tested-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Andrew de los Reyes <adlr@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
diff --git a/mux_filter.h b/mux_filter.h
index 29240f3..baaf10c 100644
--- a/mux_filter.h
+++ b/mux_filter.h
@@ -17,7 +17,7 @@
   virtual ~MuxFilter();
   void FilterFrame(Frame* previous, Frame* current, size_t num_slots);
 private:
-  scoped_array<NoiseFilter*> filters_;
+  scoped_ptr<NoiseFilter*[]> filters_;
   size_t num_filters_;
 };