Make the spell checker session static

Change-Id: I66d51f33e005f46465232d3fc460cda0609609ea

Author: satok16

api/current.txt

@@ -18463,7 +18463,7 @@ package android.service.textservice {
     field public static final java.lang.String SERVICE_INTERFACE = "android.service.textservice.SpellCheckerService";
   }
 
-  public abstract class SpellCheckerService.Session {
+  public static abstract class SpellCheckerService.Session {
     ctor public SpellCheckerService.Session();
     method public android.os.Bundle getBundle();
     method public java.lang.String getLocale();

core/java/android/service/textservice/SpellCheckerService.java

@@ -66,7 +66,7 @@ public final IBinder onBind(final Intent intent) {
     /**
      * This abstract class should be overridden by a concrete implementation of a spell checker.
      */
-    public abstract class Session {
+    public static abstract class Session {
         private InternalISpellCheckerSession mInternalSession;
 
         /**