It appears that we don't need to keep track of JavaScriptCore files in gyp since Chromium doesn't support JSC anymore and there doesn't seem to be a strong interest in using gyp as the common build system in other ports.
Created attachment 146494 [details] WIP Patch
To bake on bots. Drive-by comments welcome.
Comment on attachment 146494 [details] WIP Patch Thanks for cleaning this up. I'm sad we didn't succeed in unifying the build systems, but there isn't a strong need to keep these files around. They'll be in the svn history if we want to find them. You can also remove http://trac.webkit.org/browser/trunk/Source/gyp and http://trac.webkit.org/browser/trunk/Tools/Scripts/generate-project-files .
Committed r119921.
Looks like you left behind some empty folders. (You're probably using git.) It would be nice to use svn to delete these empty folders.
Pursuing removing the empty folders and removing more files in bug 90029.