Add SyncScheduler for scheduling CryptAuth enrollments and syncing devices.

components/proximity_auth/cryptauth/sync_scheduler.cc

+// Copyright 2015 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 "components/proximity_auth/cryptauth/sync_scheduler.h"
+
+#include "components/proximity_auth/logging/logging.h"
+
+namespace proximity_auth {
+
+SyncScheduler::SyncRequest::SyncRequest(
+    base::WeakPtr<SyncScheduler> sync_scheduler,
+    bool is_aggressive_recovery)
+    : sync_scheduler_(sync_scheduler),
+      is_aggressive_recovery_(is_aggressive_recovery),

[Ilya Sherman, 2015/05/18 23:25:38]

What is this variable used for?

[Tim Song, 2015/05/19 22:13:18]

I was going to use it to set the InvocationReason field for the requests, but I
added a GetStrategy() instead, so this is unnecessary now.

+      completed_(false) {
+}
+
+SyncScheduler::SyncRequest::~SyncRequest() {
+  if (!completed_)
+    PA_LOG(ERROR) << "SyncRequest destroyed but Complete() was never called";
+}
+
+void SyncScheduler::SyncRequest::Complete(bool success) {
+  if (sync_scheduler_) {
+    sync_scheduler_->OnSyncCompleted(success);
+    sync_scheduler_.reset();
+    completed_ = true;
+  } else {
+    PA_LOG(ERROR) << "SyncRequest completed, but SyncScheduler destroyed.";
+  }
+}
+
+}  // proximity_auth