[Android] Enable multidex for release builds of chrome_public_test_apk.

base/test/android/javatests/src/org/chromium/base/test/BaseChromiumAndroidJUnitRunner.java

 // Copyright 2017 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.base.test;
 
-import android.os.Bundle;
+import android.app.Application;
+import android.content.Context;
 import android.support.test.runner.AndroidJUnitRunner;
 
 import org.chromium.base.multidex.ChromiumMultiDexInstaller;
 
 /**
  * A custom AndroidJUnitRunner that supports multidex installer.
  *
  * This class is the equivalent of BaseChromiumInstrumentationTestRunner in JUnit3. Please
  * beware that is this not a class runner. It is declared in test apk AndroidManifest.xml
  * <instrumentation>
  */
 public class BaseChromiumAndroidJUnitRunner extends AndroidJUnitRunner {

[agrieve, 2017/04/23 01:47:52]

Does this one need @MainDex?

[jbudorick, 2017/04/24 15:04:59]

No, nor does BaseChromiumInstrumentationTestRunner. That one was a relic from
attempts at getting proguard to keep MultiDexContextWrapper.

     @Override
-    public void onCreate(Bundle arguments) {
-        ChromiumMultiDexInstaller.install(getTargetContext());
-        super.onCreate(arguments);
+    public Application newApplication(ClassLoader cl, String className, Context context)
+            throws ClassNotFoundException, IllegalAccessException, InstantiationException {
+        ChromiumMultiDexInstaller.install(new BaseChromiumRunnerCommon.MultiDexContextWrapper(
+                getContext(), getTargetContext()));
+        BaseChromiumRunnerCommon.reorderDexPathElements(cl, getContext(), getTargetContext());
+        return super.newApplication(cl, className, context);
     }
 }