white film on mother board and power button

Hi,

I have a Nexus 5. I really care for it since I use my phone for everything. I went to Fort Lauderdale for a long weekend and the day I finally make it to the beach, it doesn't turn on. Getting back to the house, I plugged it in and it just turned on and off for less than 2 seconds, so I couldn't access the reboot or start menus.

Finally, I saw a few youtube videos on the issue and it seemed like it might have been a jammed power button. After opening it up, I noticed a white film almost chalky appearance on the power button, the board itself and the plastic backing. what does this mean? Will I have to replace these pieces?