Factor out reading and writing of preferences into |PrefStore|.

In order to implement platform-specific policies, reading and writing preferences needs to be abstracted from the |PrefService|. The interface for that is now |PrefStore|, with an implementation |JsonPrefStore|, which stores the pref data in a JSON file. There is another implementation, |DummyPrefStore|, which doesn't store any persistent preferences, and is currently used for tests.

Most of the changes are for using the new interface, which is |new PrefService(new JsonPrefStore(filename))| instead of |new PrefService(filename)|.

BUG=40259
TEST=PrefServiceTest.*:PrefServiceSetValueTest.*:PrefMemberTest.*:JsonPrefStoreTest.*

Review URL: http://codereview.chromium.org/1523023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@45028 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 14 insertions, 0 deletions

diff --git a/chrome/browser/dummy_pref_store.cc b/chrome/browser/dummy_pref_store.cc
new file mode 100644
index 0000000..bd728d4
--- /dev/null
+++ b/chrome/browser/dummy_pref_store.cc
@@ -0,0 +1,14 @@
+// Copyright (c) 2010 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/dummy_pref_store.h"
+
+#include "base/values.h"
+
+DummyPrefStore::DummyPrefStore() : prefs_(new DictionaryValue()) { }
+
+PrefStore::PrefReadError DummyPrefStore::ReadPrefs() {
+  prefs_.reset(new DictionaryValue());
+  return PrefStore::PREF_READ_ERROR_NONE;
+}