Run RemoveArcData after a user has opted out

chrome/browser/chromeos/arc/arc_data_manager.h

+// Copyright 2016 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_ARC_ARC_DATA_MANAGER_H_
+#define CHROME_BROWSER_CHROMEOS_ARC_ARC_DATA_MANAGER_H_
+
+#include "base/macros.h"
+#include "base/threading/thread_checker.h"
+#include "components/arc/arc_bridge_service.h"
+
+class Profile;
+
+namespace arc {
+
+class ArcBridgeService;
+
+// This class controls the lifecycle of arc user data, removing it when

[Daniel Erat, 2016/05/12 16:33:35]

nit: s/arc/ARC/

[dspaid, 2016/05/13 01:19:25]

Done.

+// necessary.
+class ArcDataManager : public ArcBridgeService::Observer {
+ public:
+  ArcDataManager();
+  ~ArcDataManager();

[Daniel Erat, 2016/05/12 16:33:34]

override

[dspaid, 2016/05/13 01:19:24]

Done.

+
+  static ArcDataManager* Get();

[Daniel Erat, 2016/05/12 16:33:35]

if at all possible, please instead pass the instance to the classes that need to
call it. static Get() methods are error-prone, as callers have no way of knowing
when they're safe to be called during startup or shutdown, leading to either
speculative null checks or segfaults.

[dspaid, 2016/05/13 01:19:24]

I'm open to suggestions here.  The current use is in user_session_manager.cc
where similar ARC related code is accessed via static Get methods so I opted for
consistency.  I don't have an easy solution for passing an instance to the
constructor of UserSessionManager, but I could add a public SetArcDataManager
method to pass it.  However we'd still have the problem of UserSessionManager
not knowing if the instance had been set or not, so speculative null checks
would remain.

[stevenjb, 2016/05/13 17:13:54]

We should at least make this consistent with other arc services and initialize
this in ArcServiceLauncher. See other comment.

[dspaid, 2016/05/17 01:56:14]

Done.

+
+  // Checks if arc is both stopped and disabled (opt-out) and triggers removal
+  // of user data if both conditions are true.
+  void ClearIfDisabled(Profile* profile);
+
+  // Called whenever arc service state changes to potentially remove data if
+  // the user has opted out.
+  void OnStateChanged(ArcBridgeService::State state) override;

[Daniel Erat, 2016/05/12 16:33:35]

nit: add an:

  // ArcBridgeService::Observer:

comment at the top of this to document where it comes from

[dspaid, 2016/05/13 01:19:25]

Done.

+
+ private:
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(ArcDataManager);
+};
+
+}  // namespace arc
+
+#endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_DATA_MANAGER_H_