Add HAL for VR mode.

- Provide HAL for vendors to turn on VR-specific device performance
  settings when we enter VR mode in VrManagerService.

Bug: 22855417
Change-Id: I3dee920818eb0988452bf5c25d1a31f11fde7339
diff --git a/modules/vr/vr.c b/modules/vr/vr.c
new file mode 100644
index 0000000..c5af593
--- /dev/null
+++ b/modules/vr/vr.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+#define LOG_TAG "VrHal"
+
+#include <hardware/vr.h>
+#include <hardware/hardware.h>
+
+static void vr_init(struct vr_module *module) {
+    // NOOP
+}
+
+static void vr_set_vr_mode(struct vr_module *module, bool enabled) {
+    // NOOP
+}
+
+static struct hw_module_methods_t vr_module_methods = {
+    .open = NULL,
+};
+
+
+vr_module_t HAL_MODULE_INFO_SYM = {
+    .common = {
+        .tag                = HARDWARE_MODULE_TAG,
+        .module_api_version = VR_MODULE_API_VERSION_1_0,
+        .hal_api_version    = HARDWARE_HAL_API_VERSION,
+        .id                 = VR_HARDWARE_MODULE_ID,
+        .name               = "Demo VR HAL",
+        .author             = "The Android Open Source Project",
+        .methods            = &vr_module_methods,
+    },
+
+    .init = vr_init,
+    .set_vr_mode = vr_set_vr_mode,
+};