PM: Add a time provider.

This implements a time provider interface, as well as a real and a fake
implementation.

BUG=chromium:341205
TEST=Unit tests.

Change-Id: Ibc6a865ab868e0f8c760c003dc970b7987896a36
Reviewed-on: https://chromium-review.googlesource.com/190247
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/policy_manager/time_provider.h b/policy_manager/time_provider.h
new file mode 100644
index 0000000..d09097b
--- /dev/null
+++ b/policy_manager/time_provider.h
@@ -0,0 +1,53 @@
+// Copyright (c) 2014 The Chromium OS 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 CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_TIME_PROVIDER_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_TIME_PROVIDER_H_
+
+#include <base/memory/scoped_ptr.h>
+#include <base/time.h>
+
+#include "update_engine/policy_manager/provider.h"
+#include "update_engine/policy_manager/variable.h"
+
+namespace chromeos_policy_manager {
+
+// Provider for time related information.
+class TimeProvider : public Provider {
+ public:
+  // Returns the current date. The time of day component will be zero.
+  Variable<base::Time>* var_curr_date() const {
+    return var_curr_date_.get();
+  }
+
+  // Returns the current hour (0 to 23) in local time. The type is int to keep
+  // consistent with base::Time.
+  Variable<int>* var_curr_hour() const {
+    return var_curr_hour_.get();
+  }
+
+  // TODO(garnold) Implement a method/variable for querying whether a given
+  // point in time was reached.
+
+ protected:
+  TimeProvider() {}
+
+  void set_var_curr_date(Variable<base::Time>* var_curr_date) {
+    var_curr_date_.reset(var_curr_date);
+  }
+
+  void set_var_curr_hour(Variable<int>* var_curr_hour) {
+    var_curr_hour_.reset(var_curr_hour);
+  }
+
+ private:
+  scoped_ptr<Variable<base::Time>> var_curr_date_;
+  scoped_ptr<Variable<int>> var_curr_hour_;
+
+  DISALLOW_COPY_AND_ASSIGN(TimeProvider);
+};
+
+}  // namespace chromeos_policy_manager
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_TIME_PROVIDER_H_