Rename the PolicyManager to UpdateManager.

This change renames the PolicyManager class, directory, tests, etc,
to avoid confusion with libpolicy and its classes.

BUG=chromium:373551
TEST=emerged on link.
CQ-DEPEND=CL:I43081673c7ba409f02273197da7915537bde39c6

Change-Id: Iffa76caa3b95ecbbdba87ab01006d1d8ce35a27f
Reviewed-on: https://chromium-review.googlesource.com/201876
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: David Zeuthen <zeuthen@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
diff --git a/update_manager/random_provider.h b/update_manager/random_provider.h
new file mode 100644
index 0000000..dede41c
--- /dev/null
+++ b/update_manager/random_provider.h
@@ -0,0 +1,33 @@
+// 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_UPDATE_MANAGER_RANDOM_PROVIDER_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_UPDATE_MANAGER_RANDOM_PROVIDER_H_
+
+#include "update_engine/update_manager/provider.h"
+#include "update_engine/update_manager/variable.h"
+
+namespace chromeos_update_manager {
+
+// Provider of random values.
+class RandomProvider : public Provider {
+ public:
+  virtual ~RandomProvider() {}
+
+  // Return a random number every time it is requested. Note that values
+  // returned by the variables are cached by the EvaluationContext, so the
+  // returned value will be the same during the same policy request. If more
+  // random values are needed use a PRNG seeded with this value.
+  virtual Variable<uint64_t>* var_seed() = 0;
+
+ protected:
+  RandomProvider() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(RandomProvider);
+};
+
+}  // namespace chromeos_update_manager
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_UPDATE_MANAGER_RANDOM_PROVIDER_H_