components: add wifi_sync component

components/wifi_sync/wifi_credential_syncable_service.h

+// Copyright 2014 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 COMPONENTS_WIFI_SYNC_WIFI_CREDENTIAL_SYNCABLE_SERVICE_H_
+#define COMPONENTS_WIFI_SYNC_WIFI_CREDENTIAL_SYNCABLE_SERVICE_H_
+
+#include <set>
+#include <string>
+#include <utility>  // for std::pair
+#include <vector>
+
+#include "base/macros.h"
+#include "base/threading/thread_checker.h"
+#include "components/keyed_service/core/keyed_service.h"
+#include "components/wifi_sync/wifi_security_class.h"
+#include "sync/api/sync_data.h"
+#include "sync/api/sync_error.h"
+#include "sync/api/sync_error_factory.h"
+#include "sync/api/syncable_service.h"
+
+namespace content {
+class BrowserContext;
+}  // content
+
+namespace wifi_sync {
+
+// KeyedService that synchronizes WiFi credentials between local settings,
+// and Chrome Sync.
+//
+// This service does not necessarily own the storage for WiFi
+// credentials. In particular, on ChromeOS, WiFi credential storage is
+// managed by the ChromeOS connection manager ("shill").

[stevenjb, 2014/11/12 21:30:44]

nit: Shill

[mukesh agrawal, 2014/11/13 16:24:58]

Done.

+class WifiCredentialSyncableService
+    : public syncer::SyncableService, public KeyedService {
+ public:
+  // Construct a service for the given |context|. Local changes will

[stevenjb, 2014/11/12 21:30:44]

Constructs

[mukesh agrawal, 2014/11/13 16:24:58]

Done.

+  // be applied to the Chrome Sync data for the user associated with
+  // |context|.
+  explicit WifiCredentialSyncableService(content::BrowserContext *context);
+  ~WifiCredentialSyncableService() override;
+
+  // syncer::SyncableService implementation.
+  syncer::SyncMergeResult MergeDataAndStartSyncing(
+      syncer::ModelType type,
+      const syncer::SyncDataList& initial_sync_data,
+      scoped_ptr<syncer::SyncChangeProcessor> sync_processor,
+      scoped_ptr<syncer::SyncErrorFactory> error_handler) override;
+  void StopSyncing(syncer::ModelType type) override;

[stevenjb, 2014/11/12 21:30:44]

WS

[mukesh agrawal, 2014/11/13 16:24:58]

Sorry, I don't understand. What's normal practice for spacing here?

Is the problem that there's no blank line before the comment on line 50? If so,
the reason I didn't add one is that GetAllSyncData and ProcessSyncChanges still
fall under the comment at line 43. (They're part of the SyncableService
interface.)

[stevenjb, 2014/11/13 22:55:35]

So, normally overridden methods are not commented, and commented method are
spaced with a blank line. I would either:
* Move this comment to the base class header and/or the implementation
* Space all three methods and add a blank line after // syncer::SyncableService
* Leave it as-is, it's a little odd looking but we can live with it.

[mukesh agrawal, 2014/11/14 02:14:54]

Done.

Since the base class has many subclasses, I thought it'd be noisy to call out
one specific subclass there. So I've gone with option 2. 

+  // The implementation of GetAllSyncData may not actually return the
+  // complete data list. In particular, the ChromeOS implementation
+  // will return an empty list.
+  syncer::SyncDataList GetAllSyncData(syncer::ModelType type) const override;
+  syncer::SyncError ProcessSyncChanges(
+      const tracked_objects::Location& from_here,
+      const syncer::SyncChangeList& change_list) override;
+
+  // Test support.
+  std::set<std::pair<std::vector<char>, WifiSecurityClass>>

[stevenjb, 2014/11/12 21:30:44]

Maybe typedef this (with 'using')?

[mukesh agrawal, 2014/11/13 16:24:58]

Can do. Do we prefer something abstract (e.g. "WifiNetworks"), or something more
explicit (e.g. "SetOfSsidAndSecurityClassPairs")?

[stevenjb, 2014/11/13 22:55:35]

I'd split the difference, e.g. WifiSsidSecuritySet. You might want to also
typedef std::vector<char> as something like HexSsid.

[mukesh agrawal, 2014/11/14 02:14:53]

Done.

+      GetWifiNetworksForTest() const;
+
+ private:
+  friend class WifiCredentialSyncableServiceTest;
+
+  static const enum syncer::ModelType kModelType;
+
+  // Const members.
+  const content::BrowserContext* const browser_context_;
+  const base::ThreadChecker thread_checker_;
+
+  // Non-const members.
+  scoped_ptr<syncer::SyncChangeProcessor> sync_processor_;
+  scoped_ptr<syncer::SyncErrorFactory> sync_error_handler_;
+
+  DISALLOW_COPY_AND_ASSIGN(WifiCredentialSyncableService);
+};
+
+}  // namespace wifi_sync
+
+#endif  // COMPONENTS_WIFI_SYNC_WIFI_CREDENTIAL_SYNCABLE_SERVICE_H_