Add utility method to wait for bookmark model to be loaded in tests.

chrome/test/android/javatests/src/org/chromium/chrome/test/util/BookmarkTestUtil.java

Index: chrome/test/android/javatests/src/org/chromium/chrome/test/util/BookmarkTestUtil.java
diff --git a/chrome/test/android/javatests/src/org/chromium/chrome/test/util/BookmarkTestUtil.java b/chrome/test/android/javatests/src/org/chromium/chrome/test/util/BookmarkTestUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..0a2db62c7f10527f0b43a6950b6cbf7cf8632315
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+++ b/chrome/test/android/javatests/src/org/chromium/chrome/test/util/BookmarkTestUtil.java
@@ -0,0 +1,60 @@
+// Copyright 2016 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.util;
+
+import junit.framework.Assert;
+
+import org.chromium.base.ThreadUtils;
+import org.chromium.chrome.browser.bookmarks.BookmarkModel;
+import org.chromium.content.browser.test.util.CallbackHelper;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.TimeoutException;
+
+/**
+ * Utility functions for dealing with bookmarks in tests.
+ */
+public class BookmarkTestUtil {
+
+    /**
+     * Waits until the bookmark model is loaded, i.e. until
+     * {@link BookmarkModel#isBookmarkModelLoaded()} is true.
+     */
+    public static void waitForBookmarkModelLoaded() throws InterruptedException {
+        final BookmarkModel bookmarkModel = ThreadUtils.runOnUiThreadBlockingNoException(
+                new Callable<BookmarkModel>() {
+                    @Override
+                    public BookmarkModel call() throws Exception {
+                        return new BookmarkModel();
+                    }
+                });
+
+        final CallbackHelper loadedCallback = new CallbackHelper();
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                bookmarkModel.runAfterBookmarkModelLoaded(new Runnable() {
+                    @Override
+                    public void run() {
+                        loadedCallback.notifyCalled();
+                    }
+                });
+            }
+        });
+
+        try {
+            loadedCallback.waitForCallback(0);
+        } catch (TimeoutException e) {
+            Assert.fail("Bookmark model did not load: Timeout.");
+        }
+
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                bookmarkModel.destroy();
+            }
+        });
+    }
+}