Building remoting_apk produces these warnings:

===
3 warnings
[7009/7065] ACTION //remoting/android:remoting_android_client_java__compile_java__javac(//build/toolchain/android:android_clang_arm)
../../remoting/android/java/src/org/chromium/chromoting/Chromoting.java:8: warning: [deprecation] ProgressDialog in android.app has been deprecated
import android.app.ProgressDialog;
                  ^
../../remoting/android/java/src/org/chromium/chromoting/Chromoting.java:94: warning: [deprecation] ProgressDialog in android.app has been deprecated
    private ProgressDialog mProgressIndicator;
            ^
../../remoting/android/java/src/org/chromium/chromoting/Chromoting.java:532: warning: [deprecation] ProgressDialog in android.app has been deprecated
        mProgressIndicator = ProgressDialog.show(
===

From https://developer.android.com/reference/android/app/ProgressDialog.html

"This class was deprecated in API level O.
Use a progress indicator such as ProgressBar inline inside of an activity rather than using this modal dialog."