Add Context.createContextAsUser()

Without it, apps (mainline modules) will need to use createPackageContext...,
which is a bit painful.

Bug: 142472686
Test: atest android.content.cts.ContextTest#testCreateContextAsUser
Change-Id: Id640e03862462724df1a4a3101f0b08faafba22f
diff --git a/core/java/android/content/Context.java b/core/java/android/content/Context.java
index 08817e0..2dde3ae 100644
--- a/core/java/android/content/Context.java
+++ b/core/java/android/content/Context.java
@@ -5217,8 +5217,9 @@
      */
     @SystemApi
     @TestApi
+    @NonNull
     public Context createPackageContextAsUser(
-            String packageName, @CreatePackageOptions int flags, UserHandle user)
+            @NonNull String packageName, @CreatePackageOptions int flags, @NonNull UserHandle user)
             throws PackageManager.NameNotFoundException {
         if (Build.IS_ENG) {
             throw new IllegalStateException("createPackageContextAsUser not overridden!");
@@ -5227,6 +5228,23 @@
     }
 
     /**
+     * Similar to {@link #createPackageContext(String, int)}, but for the own package with a
+     * different {@link UserHandle}. For example, {@link #getContentResolver()}
+     * will open any {@link Uri} as the given user.
+     *
+     * @hide
+     */
+    @SystemApi
+    @TestApi
+    @NonNull
+    public Context createContextAsUser(@NonNull UserHandle user) {
+        if (Build.IS_ENG) {
+            throw new IllegalStateException("createContextAsUser not overridden!");
+        }
+        return this;
+    }
+
+    /**
      * Creates a context given an {@link android.content.pm.ApplicationInfo}.
      *
      * @hide