Add an API to get the last used input method subtype

Bug: 4075039

- Voice input requires to know the last used input method subtype.

Change-Id: I603a4fb88a2af5195e52188adfa6585ad80304fa
diff --git a/api/current.txt b/api/current.txt
index 4d3f8c6..9d593d8 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -22579,6 +22579,7 @@
     method public java.util.List<android.view.inputmethod.InputMethodInfo> getEnabledInputMethodList();
     method public java.util.List<android.view.inputmethod.InputMethodSubtype> getEnabledInputMethodSubtypeList(android.view.inputmethod.InputMethodInfo, boolean);
     method public java.util.List<android.view.inputmethod.InputMethodInfo> getInputMethodList();
+    method public android.view.inputmethod.InputMethodSubtype getLastInputMethodSubtype();
     method public java.util.Map<android.view.inputmethod.InputMethodInfo, java.util.List<android.view.inputmethod.InputMethodSubtype>> getShortcutInputMethodsAndSubtypes();
     method public void hideSoftInputFromInputMethod(android.os.IBinder, int);
     method public boolean hideSoftInputFromWindow(android.os.IBinder, int);