Make HandwritingGesture methods final

Make getGestureType() & getFallbackText() final since we don't expect
these methods to be overriden by concrete gestures.
This shouldn't cause any user observable behavior change.

Bug: 256016481
Test: atest CtsInputMethodTestCases
Change-Id: I865bed67089b06a572f5f085cbe04d0538928cb3

core/api/current.txt

@@ -54019,7 +54019,7 @@ package android.view.inputmethod {
   }
 
   public abstract class HandwritingGesture {
-    method @Nullable public String getFallbackText();
+    method @Nullable public final String getFallbackText();
     field public static final int GESTURE_TYPE_DELETE = 4; // 0x4
     field public static final int GESTURE_TYPE_DELETE_RANGE = 64; // 0x40
     field public static final int GESTURE_TYPE_INSERT = 2; // 0x2

core/api/test-current.txt

@@ -3181,7 +3181,7 @@ package android.view.displayhash {
 package android.view.inputmethod {
 
   public abstract class HandwritingGesture {
-    method public int getGestureType();
+    method public final int getGestureType();
   }
 
   public final class InlineSuggestion implements android.os.Parcelable {

core/java/android/view/inputmethod/HandwritingGesture.java

@@ -159,7 +159,7 @@ public abstract class HandwritingGesture {
      * @hide
      */
     @TestApi
-    public @GestureType int getGestureType() {
+    public final @GestureType int getGestureType() {
         return mType;
     }
 
@@ -173,7 +173,7 @@ public abstract class HandwritingGesture {
      * example 2: join can fail if the gesture is drawn over text but there is no whitespace.
      */
     @Nullable
-    public String getFallbackText() {
+    public final String getFallbackText() {
         return mFallbackText;
     }
 }