While looking into the dead code elimination options of GCC (bug 10394) I noticed that it completely strips the implementation of RenderTextArea. Further investigation revealed that it is now unused.
Created attachment 10032 [details] Patch
Comment on attachment 10032 [details] Patch r=me
Comment on attachment 10032 [details] Patch This patch doesn't go far enough! Four other source files that can be deleted entirely if you are deleting RenderTextArea: TextBox.h, TextBoxMac.mm, WebCoreTextArea.h, WebCoreTextArea.mm. It doesn't make sense to change the comment in WebCoreTextArea.mm -- that just makes it incorrect! What's actually going on is that's dead code too.
Committed revision 15879.