Disable access to secondary dex files.

build/android/incremental_install/java/org/chromium/incrementalinstall/ClassLoaderPatcher.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.incrementalinstall;
 
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.os.Build;
 import android.util.Log;
 
+import org.chromium.base.Reflect;
+
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.util.List;
 
 /**
  * Provides the ability to add native libraries and .dex files to an existing class loader.
  * Tested with Jellybean MR2 - Marshmellow.
@@ skipping 223 matching lines @@
                                                mClassLoader, ret);
             } else {
                 dexFile = Reflect.invokeMethod(clazz, "loadDexFile", file, optimizedDirectory);
             }
             ret[curDexElements.length + i] =
                     Reflect.newInstance(entryClazz, emptyDir, false, file, dexFile);
         }
         return ret;
     }
 }