Make FrameInfo and SurfaceInfo public.

Both are used in the public FrameProcessor interface, so they
should be public too.

PiperOrigin-RevId: 463454859
(cherry picked from commit b1b9ba82)

libraries/transformer/src/main/java/androidx/media3/transformer/FrameInfo.java

@@ -17,8 +17,11 @@ package androidx.media3.transformer;
 
 import static androidx.media3.common.util.Assertions.checkArgument;
 
+import androidx.media3.common.util.UnstableApi;
+
 /** Value class specifying information about a decoded video frame. */
-/* package */ class FrameInfo {
+@UnstableApi
+public class FrameInfo {
   /** The width of the frame, in pixels. */
   public final int width;
   /** The height of the frame, in pixels. */

libraries/transformer/src/main/java/androidx/media3/transformer/SurfaceInfo.java

@@ -19,9 +19,11 @@ import static androidx.media3.common.util.Assertions.checkArgument;
 
 import android.view.Surface;
 import androidx.annotation.Nullable;
+import androidx.media3.common.util.UnstableApi;
 
 /** Immutable value class for a {@link Surface} and supporting information. */
-/* package */ final class SurfaceInfo {
+@UnstableApi
+public final class SurfaceInfo {
 
   /** The {@link Surface}. */
   public final Surface surface;