Migrate to androidx fragment library

Change-Id: Iaf788ee4c96f4aab4ad4fb778d04a11fd5eafba0
Signed-off-by: Aayush Gupta <aayushgupta219@gmail.com>
diff --git a/Android.bp b/Android.bp
index cc89b78..f23e57d 100644
--- a/Android.bp
+++ b/Android.bp
@@ -18,11 +18,14 @@
 
 android_library {
     name: "android-opt-timezonepicker",
-    sdk_version: "17",
+    sdk_version: "current",
     srcs: [
         "src/**/*.java",
         "src/**/*.logtags",
     ],
+    static_libs: [
+        "androidx.fragment_fragment",
+    ],
 
     resource_dirs: ["res"],
 }
diff --git a/src/com/android/timezonepicker/TimeZonePickerDialog.java b/src/com/android/timezonepicker/TimeZonePickerDialog.java
index 54fd37e..ef07ff6 100644
--- a/src/com/android/timezonepicker/TimeZonePickerDialog.java
+++ b/src/com/android/timezonepicker/TimeZonePickerDialog.java
@@ -17,7 +17,6 @@
 package com.android.timezonepicker;
 
 import android.app.Dialog;
-import android.app.DialogFragment;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -25,6 +24,8 @@
 import android.view.Window;
 import android.view.WindowManager;
 
+import androidx.fragment.app.DialogFragment;
+
 public class TimeZonePickerDialog extends DialogFragment implements
         TimeZonePickerView.OnTimeZoneSetListener {
     public static final String TAG = TimeZonePickerDialog.class.getSimpleName();