Convert MultiActivityTestBase children to JUnit4

chrome/test/android/javatests/src/org/chromium/chrome/test/MultiActivityTestRule.java

Index: chrome/test/android/javatests/src/org/chromium/chrome/test/MultiActivityTestRule.java
diff --git a/chrome/test/android/javatests/src/org/chromium/chrome/test/MultiActivityTestRule.java b/chrome/test/android/javatests/src/org/chromium/chrome/test/MultiActivityTestRule.java
new file mode 100644
index 0000000000000000000000000000000000000000..98440c53f1bef7c19b7e0ff50c81b55d5c66a612
--- /dev/null
+++ b/chrome/test/android/javatests/src/org/chromium/chrome/test/MultiActivityTestRule.java
@@ -0,0 +1,60 @@
+// 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.chrome.test;
+
+import android.app.Instrumentation;
+import android.content.Context;
+import android.support.test.InstrumentationRegistry;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+import org.chromium.chrome.browser.ChromeActivity;
+import org.chromium.chrome.test.MultiActivityTestCommon.MultiActivityTestCommonCallback;
+import org.chromium.chrome.test.util.browser.tabmodel.document.MockStorageDelegate;
+
+/** Custom TestRule for MultiActivity Tests. */
+public class MultiActivityTestRule implements TestRule, MultiActivityTestCommonCallback {
+    private final MultiActivityTestCommon mTestCommon;
+
+    public MultiActivityTestRule() {
+        mTestCommon = new MultiActivityTestCommon(this);
+    }
+
+    public MockStorageDelegate getStorageDelegate() {
+        return mTestCommon.mStorageDelegate;
+    }
+
+    public Context getContext() {
+        return mTestCommon.mContext;
+    }
+
+    public void waitForFullLoad(final ChromeActivity activity, final String expectedTitle) {
+        mTestCommon.waitForFullLoad(activity, expectedTitle);
+    }
+
+    public void waitForFullLoad(
+            final ChromeActivity activity, final String expectedTitle, boolean waitLongerForLoad) {
+        mTestCommon.waitForFullLoad(activity, expectedTitle, waitLongerForLoad);
+    }
+
+    @Override
+    public Statement apply(final Statement base, Description desc) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                mTestCommon.setUp();
+                base.evaluate();
+                mTestCommon.tearDown();
+            }
+        };
+    }
+
+    @Override
+    public Instrumentation getInstrumentation() {
+        return InstrumentationRegistry.getInstrumentation();
+    }
+}