contacts: Add GoogleContactStore.

chrome/browser/chromeos/contacts/contact_store.h

+// Copyright (c) 2012 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_CHROMEOS_CONTACTS_CONTACT_STORE_H_
+#define CHROME_BROWSER_CHROMEOS_CONTACTS_CONTACT_STORE_H_
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+
+namespace contacts {
+
+class Contact;
+typedef std::vector<const Contact*> ContactPointers;
+class ContactStoreObserver;

[satorux1, 2012/08/02 22:21:25]

I thought we usually defined Observer as a nested class, like
ContactStore::Observer. However inside a class, "Observer" becomes ambiguous, if
the class observes another class's Observer...

That said, I probably like this approach better. :)

[Daniel Erat, 2012/08/02 23:23:18]

I've seen people go both ways on this.  This way usually seems safer to me, in
case I'm sending my code to a reviewer who will complain about header bloat
(i.e. all of the observer implementations' headers would need to include
contact_store.h instead of contact_store_observer.h). :-)

+
+// Interface for classes that store contacts from a particular source.
+class ContactStore {
+ public:
+  ContactStore() {}
+  virtual ~ContactStore() {}
+
+  // Appends all (non-deleted) contacts to |contacts_out|.
+  virtual void AppendContacts(ContactPointers* contacts_out) = 0;
+
+  // Returns the contact identified by |provider_id|.
+  // NULL is returned if the contact doesn't exist.
+  virtual const Contact* GetContactByProviderId(
+      const std::string& provider_id) = 0;
+
+  // Adds or removes an observer.
+  virtual void AddObserver(ContactStoreObserver* observer) = 0;
+  virtual void RemoveObserver(ContactStoreObserver* observer) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ContactStore);
+};
+
+}  // namespace contacts
+
+#endif  // CHROME_BROWSER_CHROMEOS_CONTACTS_CONTACT_STORE_H_