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/evaluation_context-inl.h b/update_manager/evaluation_context-inl.h
new file mode 100644
index 0000000..962d0e9
--- /dev/null
+++ b/update_manager/evaluation_context-inl.h
@@ -0,0 +1,41 @@
+// 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_EVALUATION_CONTEXT_INL_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_UPDATE_MANAGER_EVALUATION_CONTEXT_INL_H_
+
+#include <base/logging.h>
+
+namespace chromeos_update_manager {
+
+template<typename T>
+const T* EvaluationContext::GetValue(Variable<T>* var) {
+  if (var == nullptr) {
+    LOG(ERROR) << "GetValue received an uninitialized variable.";
+    return nullptr;
+  }
+
+  // Search for the value on the cache first.
+  ValueCacheMap::iterator it = value_cache_.find(var);
+  if (it != value_cache_.end())
+    return reinterpret_cast<const T*>(it->second.value());
+
+  // Get the value from the variable if not found on the cache.
+  std::string errmsg;
+  const T* result = var->GetValue(RemainingTime(), &errmsg);
+  if (result == nullptr) {
+    LOG(WARNING) << "Error reading Variable " << var->GetName() << ": \""
+        << errmsg << "\"";
+  }
+  // Cache the value for the next time. The map of CachedValues keeps the
+  // ownership of the pointer until the map is destroyed.
+  value_cache_.emplace(
+    static_cast<BaseVariable*>(var),
+    std::move(BoxedValue(result)));
+  return result;
+}
+
+}  // namespace chromeos_update_manager
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_UPDATE_MANAGER_EVALUATION_CONTEXT_INL_H_