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

The CL now applies after r45225 (Throw out preferences files that are corrupt rather than keeping them in read-only mode), which means that the changes in that commit moved to JsonPrefStore.

I updated JsonPrefStoreTest.InvalidFile to test the new behavior.

***

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/1717007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@45309 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 27 insertions, 0 deletions

diff --git a/chrome/browser/dummy_pref_store.h b/chrome/browser/dummy_pref_store.h
new file mode 100644
index 0000000..16075c4
--- /dev/null
+++ b/chrome/browser/dummy_pref_store.h
@@ -0,0 +1,27 @@
+// 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.
+
+#ifndef CHROME_BROWSER_DUMMY_PREF_STORE_H_
+#define CHROME_BROWSER_DUMMY_PREF_STORE_H_
+
+#include "base/basictypes.h"
+#include "base/scoped_ptr.h"
+#include "chrome/browser/pref_store.h"
+
+class DummyPrefStore : public PrefStore {
+ public:
+  DummyPrefStore();
+
+  virtual DictionaryValue* Prefs() { return prefs_.get(); }
+  void SetPrefs(DictionaryValue* prefs) { prefs_.reset(prefs); }
+
+  virtual PrefStore::PrefReadError ReadPrefs();
+
+ private:
+  scoped_ptr<DictionaryValue> prefs_;
+
+  DISALLOW_COPY_AND_ASSIGN(DummyPrefStore);
+};
+
+#endif  // CHROME_BROWSER_DUMMY_PREF_STORE_H_