Use renameTo safely when creating the user 0 account database

* Because the user directory probably won't exist, the renameTo
  in previous code fails silently

Bug: 6188815
Change-Id: I6afd1bad9bbd1a36de7e93d9e02ed7172b1ed370

Author: Marc Blank

core/java/android/accounts/AccountManagerService.java

@@ -1817,7 +1817,16 @@ private static String getDatabaseName(int userId) {
             // Migrate old file, if it exists, to the new location
             File oldFile = new File(systemDir, DATABASE_NAME);
             if (oldFile.exists()) {
-                oldFile.renameTo(databaseFile);
+                // Check for use directory; create if it doesn't exist, else renameTo will fail
+                File userDir = new File(systemDir, "users/" + userId);
+                if (!userDir.exists()) {
+                    if (!userDir.mkdirs()) {
+                        throw new IllegalStateException("User dir cannot be created: " + userDir);
+                    }
+                }
+                if (!oldFile.renameTo(databaseFile)) {
+                    throw new IllegalStateException("User dir cannot be migrated: " + databaseFile);
+                }
             }
         }
         return databaseFile.getPath();