Adding a new annotation to set ChildProcessAllocator settings in tests.

content/public/test/android/javatests/src/org/chromium/content/browser/test/ChildProcessAllocatorSettingsHook.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.content.browser.test;
+
+import android.content.Context;
+
+import org.chromium.base.test.BaseTestResult.PreTestHook;
+import org.chromium.content.browser.ChildProcessLauncher;
+
+import java.lang.reflect.Method;
+
+/** PreTestHook used to register the ChildProcessAllocatorSettings annotation. */
+public final class ChildProcessAllocatorSettingsHook implements PreTestHook {
+    @Override
+    public void run(Context targetContext, Method testMethod) {
+        ChildProcessAllocatorSettings annotation =
+                testMethod.getAnnotation(ChildProcessAllocatorSettings.class);
+        if (annotation != null) {
+            ChildProcessLauncher.setSanboxServicesSettingsForTesting(
+                    annotation.sandboxedServiceCount(), annotation.sandboxedServiceName());
+        }
+    }
+}