An <input>'s inline style declaration overrides the -webkit-input-placeholder-mode pseudo-class declaration, causing the placeholder text to have the color specified in inline style. For example, <input style="color: black;" placeholder="holding"> will show "holding" in black instead of dark gray.
I'll switch to using a pseudo element. bah.
Created attachment 24034 [details] patch
Comment on attachment 24034 [details] patch r=me!
Committed revision 37217