diff --git a/gnss/1.0/default/GnssXtra.h b/gnss/1.0/default/GnssXtra.h
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+++ b/gnss/1.0/default/GnssXtra.h
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+/*
+ * 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.
+ */
+
+#ifndef android_hardware_gnss_V1_0_GnssXtra_H_
+#define android_hardware_gnss_V1_0_GnssXtra_H_
+
+#include <ThreadCreationWrapper.h>
+#include <android/hardware/gnss/1.0/IGnssXtra.h>
+#include <hardware/gps.h>
+#include <hidl/Status.h>
+
+namespace android {
+namespace hardware {
+namespace gnss {
+namespace V1_0 {
+namespace implementation {
+
+using ::android::hardware::gnss::V1_0::IGnssXtra;
+using ::android::hardware::gnss::V1_0::IGnssXtraCallback;
+using ::android::hardware::Return;
+using ::android::hardware::Void;
+using ::android::hardware::hidl_vec;
+using ::android::hardware::hidl_string;
+using ::android::sp;
+
+/*
+ * This interface is used by the GNSS HAL to request the framework to download XTRA data.
+ * Also contains wrapper methods to allow methods from IGnssXtraCallback interface to be passed
+ * into the conventional implementation of the GNSS HAL.
+ */
+struct GnssXtra : public IGnssXtra {
+    GnssXtra(const GpsXtraInterface* xtraIface);
+    ~GnssXtra();
+
+    /*
+     * Methods from ::android::hardware::gnss::V1_0::IGnssXtra follow.
+     * These declarations were generated from IGnssXtra.hal.
+     */
+    Return<bool> setCallback(const sp<IGnssXtraCallback>& callback) override;
+    Return<bool> injectXtraData(const hidl_string& xtraData) override;
+
+    /*
+     * Callback methods to be passed into the conventional GNSS HAL by the default implementation.
+     * These methods are not part of the IGnssXtra base class.
+     */
+    static pthread_t createThreadCb(const char* name, void (*start)(void*), void* arg);
+    static void gnssXtraDownloadRequestCb();
+
+    /*
+     * Holds function pointers to the callback methods.
+     */
+    static GpsXtraCallbacks sGnssXtraCb;
+
+ private:
+    const GpsXtraInterface* mGnssXtraIface = nullptr;
+    static sp<IGnssXtraCallback> sGnssXtraCbIface;
+    static std::vector<std::unique_ptr<ThreadFuncArgs>> sThreadFuncArgsList;
+    static bool sInterfaceExists;
+};
+
+}  // namespace implementation
+}  // namespace V1_0
+}  // namespace gnss
+}  // namespace hardware
+}  // namespace android
+
+#endif  // android_hardware_gnss_V1_0_GnssXtra_H_