[Sync] PassphraseActivity: unregister for sync events when paused.

chrome/android/javatests/src/org/chromium/chrome/browser/sync/FakeProfileSyncService.java

Index: chrome/android/javatests/src/org/chromium/chrome/browser/sync/FakeProfileSyncService.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/sync/FakeProfileSyncService.java b/chrome/android/javatests/src/org/chromium/chrome/browser/sync/FakeProfileSyncService.java
new file mode 100644
index 0000000000000000000000000000000000000000..46ba2ccdbd0a12ce15285b66cc0eb84fbcd2b2ac
--- /dev/null
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/sync/FakeProfileSyncService.java
@@ -0,0 +1,35 @@
+// Copyright 2015 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.browser.sync;
+
+import android.content.Context;
+
+/**
+ * Fake some ProfileSyncService methods for testing.
+ *
+ * Only what has been needed for tests so far has been faked.
+ */
+public class FakeProfileSyncService extends ProfileSyncService {
+
+    private boolean mBackendInitialized;
+
+    public FakeProfileSyncService(Context context) {
+        super(context);
+    }
+
+    @Override
+    public boolean isSyncInitialized() {
+        return mBackendInitialized;
+    }
+
+    public void setSyncInitialized(boolean syncInitialized) {
+        mBackendInitialized = syncInitialized;
+    }
+
+    @Override
+    public boolean isUsingSecondaryPassphrase() {
+        return true;
+    }
+}