Make TabView a public final class since a field of that type is in th…

…e 1.0.0 public API

Reference: https://github.com/material-components/material-components-android/blob/master/lib/java/com/google/android/material/tabs/TabLayout.java#L1888

Resolves #581

PiperOrigin-RevId: 272592933
(cherry picked from commit 440fea0)

lib/java/com/google/android/material/tabs/TabLayout.java

@@ -2212,7 +2212,8 @@ void reset() {
     }
   }
 
-  class TabView extends LinearLayout {
+  /** A {@link LinearLayout} containing {@link Tab} instances for use with {@link TabLayout}. */
+  public final class TabView extends LinearLayout {
     private Tab tab;
     private TextView textView;
     private ImageView iconView;
@@ -2226,7 +2227,7 @@ class TabView extends LinearLayout {
 
     private int defaultMaxLines = 2;
 
-    public TabView(Context context) {
+    public TabView(@NonNull Context context) {
       super(context);
       updateBackgroundDrawable(context);
       ViewCompat.setPaddingRelative(
@@ -2798,6 +2799,7 @@ private int getContentWidth() {
       return right - left;
     }
 
+    @Nullable
     public Tab getTab() {
       return tab;
     }