GoogleTV and Android in Blink sets the keycodes 0xE3 and 0xE4 for the rewind and fast forward keys. This is already used by several TV oriented websites due to GoogleTV.
Created attachment 204689 [details] Patch
Created attachment 204693 [details] Patch Removed the VK definitions since they were unofficial, and have been defined differently on Windows Embedded
Created attachment 204700 [details] Patch Found the source of the other VK definition
Committed r151588: <http://trac.webkit.org/changeset/151588>