Add vr platform lib

Add the vr platform library, which allows client code to load the dvr
api and access the getVrBoot() method.

Bug: 38134403
Test: Booted a Marlin.

Change-Id: I884a623ec9a297a2973f1c42c3da094c6c155630

vr/Android.mk

@@ -0,0 +1,38 @@
+# 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.
+LOCAL_PATH := $(call my-dir)
+
+# Library to perform dlopen on the actual shared library.
+include $(CLEAR_VARS)
+LOCAL_MODULE := libdvr_loader
+LOCAL_MODULE_OWNER := google
+LOCAL_SRC_FILES := dvr_library_loader.cpp
+include $(BUILD_SHARED_LIBRARY)
+
+# Java platform library for vr stuff.
+include $(CLEAR_VARS)
+LOCAL_MODULE := com.google.vr.platform
+LOCAL_MODULE_OWNER := google
+LOCAL_REQUIRED_MODULES := libdvr_loader libdvr
+LOCAL_SRC_FILES := $(call all-java-files-under, java)
+include $(BUILD_JAVA_LIBRARY)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := com.google.vr.platform.xml
+LOCAL_SRC_FILES := com.google.vr.platform.xml
+LOCAL_MODULE_TAGS := optional
+LOCAL_MODULE_CLASS := ETC
+LOCAL_MODULE_OWNER := google
+LOCAL_MODULE_PATH := $(TARGET_OUT_ETC)/permissions
+include $(BUILD_PREBUILT)

vr/com.google.vr.platform.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- 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.
+-->
+
+<permissions>
+    <library name="com.google.vr.platform"
+             file="/system/framework/com.google.vr.platform.jar" />
+</permissions>

vr/dvr_library_loader.cpp

@@ -0,0 +1,25 @@
+#include <dlfcn.h>
+#include <jni.h>
+
+#include <string>
+
+extern "C" {
+
+JNIEXPORT jlong JNICALL
+Java_com_google_vr_platform_Dvr_nativeLoadLibrary(
+    JNIEnv* env, jclass, jstring java_library) {
+  if (!java_library)
+    return 0;
+
+  // Convert the Java String object to a C++ null-terminated string.
+  const char* data = env->GetStringUTFChars(java_library, NULL);
+  size_t size = env->GetStringUTFLength(java_library);
+  std::string library(data, size);
+  env->ReleaseStringUTFChars(java_library, data);
+
+  // Return the handle to the requested library.
+  return reinterpret_cast<jlong>(
+      dlopen(library.c_str(), RTLD_NOW | RTLD_LOCAL));
+}
+
+}  // extern "C"

vr/java/com/google/vr/platform/DeviceInfo.java

@@ -0,0 +1,19 @@
+package com.google.vr.platform;
+
+import android.os.SystemProperties;
+
+/**
+ * Class to get information about the vr device.
+ * @hide
+ */
+public class DeviceInfo {
+
+    private static final String VR_MODE_BOOT = "ro.boot.vr";
+
+    /**
+     * Returns true if this device boots directly in VR mode.
+     */
+    public static boolean getVrBoot() {
+        return SystemProperties.getBoolean(VR_MODE_BOOT, false);
+    }
+}

vr/java/com/google/vr/platform/Dvr.java

@@ -0,0 +1,22 @@
+package com.google.vr.platform;
+
+/**
+ * Class to load the dvr api.
+ * @hide
+ */
+public class Dvr {
+    /**
+     * Opens a shared library containing the dvr api and returns the handle to it.
+     *
+     * @return A Long object describing the handle returned by dlopen.
+     */
+    public static Long loadLibrary() {
+        // Load a thin JNI library that runs dlopen on request.
+        System.loadLibrary("dvr_loader");
+
+        // Performs dlopen on the library and returns the handle.
+        return nativeLoadLibrary("libdvr.so");
+    }
+
+    private static native long nativeLoadLibrary(String library);
+}