[Android] Add gyp support for multidex.

base/test/android/junit/src/org/chromium/base/test/shadows/ShadowMultiDex.java

Index: base/test/android/junit/src/org/chromium/base/test/shadows/ShadowMultiDex.java
diff --git a/base/test/android/junit/src/org/chromium/base/test/shadows/ShadowMultiDex.java b/base/test/android/junit/src/org/chromium/base/test/shadows/ShadowMultiDex.java
new file mode 100644
index 0000000000000000000000000000000000000000..b3ff57e372e5aa2c55b981bab8920585cfee70ee
--- /dev/null
+++ b/base/test/android/junit/src/org/chromium/base/test/shadows/ShadowMultiDex.java
@@ -0,0 +1,21 @@
+// 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.base.test.shadows;
+
+import android.content.Context;
+import android.support.multidex.MultiDex;
+
+import org.robolectric.annotation.Implementation;
+import org.robolectric.annotation.Implements;
+
+/** Do-nothing shadow for {@link android.support.multidex.MultiDex}. */
+@Implements(MultiDex.class)
+public class ShadowMultiDex {
+
+    @Implementation
+    public static void install(Context context) {
+    }
+
+}