Firstly, as you have read before, WRITE_SECURE_SETTINGS is NOT available to applications! So you cannot use this permission regardless whether you are on rooted or production builds.
So, if you wish to enable this setting, create your own firmware that does what you need and load that firmware on whatever devices you wish. Or, contribute your changes to existing firmware mods (e.g., Cyanogen).
Some other applications use techniques like Reflection
using Java to gain access to functions not exposed via API, you can probably try the same.
Secondly, adb remount
does not work as is with production builds unless the phone is rooted or firmware enables it by default.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…