Fix incremental install for Android N

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.content.Context;
 import android.os.Build;
 import android.util.Log;
 
@@ skipping 75 matching lines @@
             }
         }
 
         Log.i(TAG, "Code cache dir: " + optimizedDir);
         // TODO(agrieve): Might need to record classpath ordering if we ever have duplicate
         //     class names (since then order will matter here).
         Log.i(TAG, "Loading " + dexFilesArr.length + " dex files");
 
         Object dexPathList = Reflect.getField(mClassLoader, "pathList");
         Object[] dexElements = (Object[]) Reflect.getField(dexPathList, "dexElements");
-        Object[] additionalElements = makeDexElements(dexFilesArr, optimizedDir);
-        Reflect.setField(dexPathList, "dexElements",
-                Reflect.concatArrays(dexElements, dexElements, additionalElements));
+        dexElements = addDexElements(dexFilesArr, optimizedDir, dexElements);
+        Reflect.setField(dexPathList, "dexElements", dexElements);
     }
 
     /**
      * Sets up all libraries within |libDir| to be loadable by System.loadLibrary().
      */
     void importNativeLibs(File libDir) throws ReflectiveOperationException, IOException {
         Log.i(TAG, "Importing native libraries from: " + libDir);
         if (!libDir.exists()) {
             Log.i(TAG, "No native libs exist.");
             return;
@@ skipping 106 matching lines @@
     private static Object[] makeNativePathElements(File[] paths)
             throws ReflectiveOperationException {
         Class<?> entryClazz = Class.forName("dalvik.system.DexPathList$Element");
         Object[] entries = new Object[paths.length];
         for (int i = 0; i < paths.length; ++i) {
             entries[i] = Reflect.newInstance(entryClazz, paths[i], true, null, null);
         }
         return entries;
     }
 
-    private static Object[] makeDexElements(File[] files, File optimizedDirectory)
+    private Object[] addDexElements(File[] files, File optimizedDirectory, Object[] curDexElements)
             throws ReflectiveOperationException {
         Class<?> entryClazz = Class.forName("dalvik.system.DexPathList$Element");
         Class<?> clazz = Class.forName("dalvik.system.DexPathList");
-        Object[] entries = new Object[files.length];
+        Object[] ret =
+                Reflect.concatArrays(curDexElements, curDexElements, new Object[files.length]);
         File emptyDir = new File("");
         for (int i = 0; i < files.length; ++i) {
             File file = files[i];
-            Object dexFile = Reflect.invokeMethod(clazz, "loadDexFile", file, optimizedDirectory);
-            entries[i] = Reflect.newInstance(entryClazz, emptyDir, false, file, dexFile);
+            Object dexFile;
+            if ("N".equals(Build.VERSION.CODENAME)) {
+                // loadDexFile requires that ret contain all previously added elements.
+                dexFile = Reflect.invokeMethod(clazz, "loadDexFile", file, optimizedDirectory,
+                                               mClassLoader, ret);
+            } else {
+                dexFile = Reflect.invokeMethod(clazz, "loadDexFile", file, optimizedDirectory);
+            }
+            ret[curDexElements.length + i] =
+                    Reflect.newInstance(entryClazz, emptyDir, false, file, dexFile);
         }
-        return entries;
+        return ret;
     }
 }