Make Android Clipboard Keep Track of Last Modified Time

ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java

Index: ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java
diff --git a/ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java b/ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..a4bd96668dbe8fa699626bf578b8f64cbd693cf4
--- /dev/null
+++ b/ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java
@@ -0,0 +1,50 @@
+// 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.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+
+import org.chromium.base.ContextUtils;
+import org.chromium.base.metrics.RecordHistogram;
+import org.chromium.base.metrics.RecordUserAction;
+import org.chromium.testing.local.LocalRobolectricTestRunner;
+
+/**
+ * Tests logic in the Clipboard class.
+ */
+@RunWith(LocalRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class ClipboardTest {
+    @BeforeClass
+    public static void beforeClass() {
+        RecordHistogram.setDisabledForTests(true);
+        RecordUserAction.setDisabledForTests(true);
+    }
+
+    @AfterClass
+    public static void afterClass() {
+        RecordHistogram.setDisabledForTests(false);
+        RecordUserAction.setDisabledForTests(false);
+    }
+
+    @Test
+    public void testGetClipboardContentChangeTimeInMillis() {
+        ContextUtils.initApplicationContext(RuntimeEnvironment.application);
+        // Upon launch, the clipboard should be at start of epoch, i.e., ancient.
+        Clipboard clipboard = Clipboard.getInstance();
+        assertEquals(0, clipboard.getClipboardContentChangeTimeInMillis());
+        // After updating the clipboard, it should have a new time.
+        clipboard.onPrimaryClipChanged();
+        assertTrue(clipboard.getClipboardContentChangeTimeInMillis() > 0);
+    }
+}