Add additional overriding methods to signature files

This change adds overriding methods that are essential to compile the
stubs generated from the signature files.

More information and the background for this change is available at go/add-overriding-one-pager.

Test: m checkbuild --build-from-text-stub
Bug: 299366704
(cherry picked from https://android-review.googlesource.com/q/commit:a0f6b3c00bda4231c054624f36dd6e5c50102c9c)
Merged-In: I610d2ebbbd42bc3004504d2aef4c5c408e635fe5
Change-Id: I610d2ebbbd42bc3004504d2aef4c5c408e635fe5
diff --git a/android_icu4j/api/intra/current.txt b/android_icu4j/api/intra/current.txt
index 1626068..cdba19f 100644
--- a/android_icu4j/api/intra/current.txt
+++ b/android_icu4j/api/intra/current.txt
@@ -1,6 +1,4 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
 package com.android.i18n.system {
 
   public class AppSpecializationHooks {
diff --git a/android_icu4j/api/intra/removed.txt b/android_icu4j/api/intra/removed.txt
index 14191eb..d802177 100644
--- a/android_icu4j/api/intra/removed.txt
+++ b/android_icu4j/api/intra/removed.txt
@@ -1,3 +1 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
diff --git a/android_icu4j/api/legacy_platform/current.txt b/android_icu4j/api/legacy_platform/current.txt
index 78af160..ca3fafb 100644
--- a/android_icu4j/api/legacy_platform/current.txt
+++ b/android_icu4j/api/legacy_platform/current.txt
@@ -1,6 +1,4 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
 package android.icu.text {
 
   public class DateFormatSymbols implements java.lang.Cloneable java.io.Serializable {
diff --git a/android_icu4j/api/legacy_platform/removed.txt b/android_icu4j/api/legacy_platform/removed.txt
index 14191eb..d802177 100644
--- a/android_icu4j/api/legacy_platform/removed.txt
+++ b/android_icu4j/api/legacy_platform/removed.txt
@@ -1,3 +1 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
diff --git a/android_icu4j/api/public/current.txt b/android_icu4j/api/public/current.txt
index ceb633a..ee59067 100644
--- a/android_icu4j/api/public/current.txt
+++ b/android_icu4j/api/public/current.txt
@@ -1,6 +1,4 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
 package android.icu.lang {
 
   public final class UCharacter implements android.icu.lang.UCharacterEnums.ECharacterCategory android.icu.lang.UCharacterEnums.ECharacterDirection {
@@ -1717,6 +1715,7 @@
     method public CharSequence subSequence(int, int);
     method public java.math.BigDecimal toBigDecimal();
     method public java.text.AttributedCharacterIterator toCharacterIterator();
+    method public String toString();
   }
 
   public class FormattedNumberRange implements android.icu.text.FormattedValue {
@@ -1729,6 +1728,7 @@
     method public boolean nextPosition(android.icu.text.ConstrainedFieldPosition);
     method public CharSequence subSequence(int, int);
     method public java.text.AttributedCharacterIterator toCharacterIterator();
+    method public String toString();
   }
 
   public abstract class FractionPrecision extends android.icu.number.Precision {
@@ -2201,6 +2201,7 @@
     method public android.icu.text.Collator cloneAsThawed();
     method public abstract int compare(String, String);
     method public int compare(Object, Object);
+    method public boolean equals(Object);
     method public boolean equals(String, String);
     method public android.icu.text.Collator freeze();
     method public static java.util.Locale[] getAvailableLocales();
@@ -2578,6 +2579,7 @@
     method public boolean nextPosition(android.icu.text.ConstrainedFieldPosition);
     method public CharSequence subSequence(int, int);
     method public java.text.AttributedCharacterIterator toCharacterIterator();
+    method public String toString();
   }
 
   public class DateIntervalInfo implements java.lang.Cloneable android.icu.util.Freezable<android.icu.text.DateIntervalInfo> java.io.Serializable {
@@ -2949,6 +2951,7 @@
     method public boolean nextPosition(android.icu.text.ConstrainedFieldPosition);
     method public CharSequence subSequence(int, int);
     method public java.text.AttributedCharacterIterator toCharacterIterator();
+    method public String toString();
   }
 
   public enum ListFormatter.Type {
@@ -3414,6 +3417,7 @@
     method public boolean nextPosition(android.icu.text.ConstrainedFieldPosition);
     method public CharSequence subSequence(int, int);
     method public java.text.AttributedCharacterIterator toCharacterIterator();
+    method public String toString();
   }
 
   public enum RelativeDateTimeFormatter.RelativeDateTimeUnit {
diff --git a/android_icu4j/api/public/module-lib-current.txt b/android_icu4j/api/public/module-lib-current.txt
index 14191eb..d802177 100644
--- a/android_icu4j/api/public/module-lib-current.txt
+++ b/android_icu4j/api/public/module-lib-current.txt
@@ -1,3 +1 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
diff --git a/android_icu4j/api/public/module-lib-removed.txt b/android_icu4j/api/public/module-lib-removed.txt
index 14191eb..d802177 100644
--- a/android_icu4j/api/public/module-lib-removed.txt
+++ b/android_icu4j/api/public/module-lib-removed.txt
@@ -1,3 +1 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
diff --git a/android_icu4j/api/public/removed.txt b/android_icu4j/api/public/removed.txt
index 2249460..e73b663 100644
--- a/android_icu4j/api/public/removed.txt
+++ b/android_icu4j/api/public/removed.txt
@@ -1,6 +1,4 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
 package android.icu.util {
 
   public class JapaneseCalendar extends android.icu.util.GregorianCalendar {
diff --git a/android_icu4j/api/public/system-current.txt b/android_icu4j/api/public/system-current.txt
index 14191eb..d802177 100644
--- a/android_icu4j/api/public/system-current.txt
+++ b/android_icu4j/api/public/system-current.txt
@@ -1,3 +1 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
diff --git a/android_icu4j/api/public/system-removed.txt b/android_icu4j/api/public/system-removed.txt
index 14191eb..d802177 100644
--- a/android_icu4j/api/public/system-removed.txt
+++ b/android_icu4j/api/public/system-removed.txt
@@ -1,3 +1 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
diff --git a/android_icu4j/api/stable_platform/current.txt b/android_icu4j/api/stable_platform/current.txt
index 14191eb..d802177 100644
--- a/android_icu4j/api/stable_platform/current.txt
+++ b/android_icu4j/api/stable_platform/current.txt
@@ -1,3 +1 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704
diff --git a/android_icu4j/api/stable_platform/removed.txt b/android_icu4j/api/stable_platform/removed.txt
index 14191eb..d802177 100644
--- a/android_icu4j/api/stable_platform/removed.txt
+++ b/android_icu4j/api/stable_platform/removed.txt
@@ -1,3 +1 @@
 // Signature format: 2.0
-// - add-additional-overrides=no
-// - migrating=Migration in progress see b/299366704