libbinder_ndk: add read/write string methods.

utf16 is left on the wire, but utf8 is exposed in the NDK.

Bug: 111445392
Test: atest android.binder.cts
Change-Id: Ie4f19ba52dc2323b1c6cf0c4b5e60c7bf2802cf8
diff --git a/libs/binder/ndk/libbinder_ndk.map.txt b/libs/binder/ndk/libbinder_ndk.map.txt
index 4f486c9..2a1bff1 100644
--- a/libs/binder/ndk/libbinder_ndk.map.txt
+++ b/libs/binder/ndk/libbinder_ndk.map.txt
@@ -32,6 +32,7 @@
     AParcel_readInt64;
     AParcel_readNullableStrongBinder;
     AParcel_readStatusHeader;
+    AParcel_readString;
     AParcel_readStrongBinder;
     AParcel_readUint32;
     AParcel_readUint64;
@@ -43,6 +44,7 @@
     AParcel_writeInt32;
     AParcel_writeInt64;
     AParcel_writeStatusHeader;
+    AParcel_writeString;
     AParcel_writeStrongBinder;
     AParcel_writeUint32;
     AParcel_writeUint64;