Make Android Clipboard Keep Track of Last Modified Time

ui/android/junit/src/org/chromium/ui/base/ClipboardTest.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.ui.base;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.annotation.Config;
+
+import org.chromium.base.test.util.AdvancedMockContext;
+import org.chromium.testing.local.LocalRobolectricTestRunner;
+
+/**
+ * Tests logic in the Clipboard class.
+ */
+@RunWith(LocalRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class ClipboardTest {
+    @Test
+    public void testGetClipboardContentChangeTimeInMillis() {
+        // Upon launch, the clipboard should be at start of epoch, i.e., ancient.
+        Clipboard clipboard = new Clipboard(new AdvancedMockContext());
+        assertEquals(0, clipboard.getClipboardContentChangeTimeInMillis());
+        // After updating the clipboard, it should have a new time.
+        clipboard.onPrimaryClipChanged();
+        assertTrue(clipboard.getClipboardContentChangeTimeInMillis() > 0);
+    }
+}