Introduce ManifestUpgradeDetector for WebAPK to detect web manifest changes.

chrome/browser/android/webapk/manifest_upgrade_detector_unittest.cc

Index: chrome/browser/android/webapk/manifest_upgrade_detector_unittest.cc
diff --git a/chrome/browser/android/webapk/manifest_upgrade_detector_unittest.cc b/chrome/browser/android/webapk/manifest_upgrade_detector_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..330140e1ad5522de27223800802f05c872f51999
--- /dev/null
+++ b/chrome/browser/android/webapk/manifest_upgrade_detector_unittest.cc
@@ -0,0 +1,20 @@
+// 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.
+
+#include "chrome/browser/android/webapk/manifest_upgrade_detector.h"
+#include "content/public/common/manifest.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using ManifestUpgradeDetectorTest = testing::Test;
+
+TEST_F(ManifestUpgradeDetectorTest,
+       OnDidGetManifestReturnsFalseWhenTheFetchedManifestUrlIsEmpty) {
+  ManifestUpgradeDetector detector(nullptr, jobject(), nullptr, GURL(), GURL());
+  EXPECT_EQ(ManifestUpgradeDetector::NoErrorDetected, detector.error_code());
+
+  content::Manifest manifest;
+  detector.OnDidGetManifest(GURL(), manifest);
+  EXPECT_EQ(ManifestUpgradeDetector::FetchedManifestEmpty,
+            detector.error_code());
+}