Get mojo_shell building inside chromium checkout.

mojo/shell/android/tests/src/org/chromium/mojo/shell/ShellTestBase.java

+// Copyright 2014 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.mojo.shell;
+
+import android.content.Context;
+import android.content.res.AssetManager;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Helper method for ShellTestBase.
+ */
+@JNINamespace("mojo::shell::test")
+public class ShellTestBase {
+    // Directory where applications bundled with the tests will be extracted.
+    private static final String TEST_APP_DIRECTORY = "test_apps";
+
+    /**
+     * Extracts the mojo applications from the apk assets and returns the directory where they are.
+     */
+    @CalledByNative
+    private static String extractMojoApplications(Context context) throws IOException {
+        final File outputDirectory = context.getDir(TEST_APP_DIRECTORY, Context.MODE_PRIVATE);
+
+        AssetManager manager = context.getResources().getAssets();
+        for (String asset : manager.list("")) {
+            if (asset.endsWith(".mojo")) {
+                FileHelper.extractFromAssets(context, asset, outputDirectory, false);
+            }
+        }
+
+        return outputDirectory.getAbsolutePath();
+    }
+}