Add VintfObject as the top level API.

VintfObject has:
  GetDeviceHalManifest (replace HalManifest::Get)
  GetRuntimeInfo (replace RuntimeInfo::Get)
  GetFrameworkHalManifest

Test: vintf
Test: libvintf_test
Change-Id: I6c1f0e6af0ea323054102bf713667c23dbc10972
diff --git a/VintfObject.cpp b/VintfObject.cpp
new file mode 100644
index 0000000..65071a0
--- /dev/null
+++ b/VintfObject.cpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "VintfObject.h"
+
+#include <functional>
+#include <memory>
+#include <mutex>
+
+namespace android {
+namespace vintf {
+
+template <typename T>
+struct LockedUniquePtr {
+    std::unique_ptr<T> object;
+    std::mutex mutex;
+};
+
+static LockedUniquePtr<HalManifest> gDeviceManifest;
+static LockedUniquePtr<HalManifest> gFrameworkManifest;
+static LockedUniquePtr<RuntimeInfo> gDeviceRuntimeInfo;
+
+template <typename T, typename F>
+static const T *Get(
+        LockedUniquePtr<T> *ptr,
+        const F &fetchAllInformation) {
+    std::unique_lock<std::mutex> _lock(ptr->mutex);
+    if (ptr->object == nullptr) {
+        ptr->object = std::make_unique<T>();
+        if (fetchAllInformation(ptr->object.get()) != OK) {
+            ptr->object = nullptr; // frees the old object
+        }
+    }
+    return ptr->object.get();
+}
+
+// static
+const HalManifest *VintfObject::GetDeviceHalManifest() {
+    return Get(&gDeviceManifest,
+            std::bind(&HalManifest::fetchAllInformation, std::placeholders::_1,
+                "/vendor/manifest.xml"));
+}
+
+// static
+const HalManifest *VintfObject::GetFrameworkHalManifest() {
+    return Get(&gFrameworkManifest,
+            std::bind(&HalManifest::fetchAllInformation, std::placeholders::_1,
+                "/system/manifest.xml"));
+}
+
+// static
+const RuntimeInfo *VintfObject::GetRuntimeInfo() {
+    return Get(&gDeviceRuntimeInfo,
+            std::bind(&RuntimeInfo::fetchAllInformation, std::placeholders::_1));
+}
+
+
+} // namespace vintf
+} // namespace android