In r151854 we added copying of ANGLE headers before in WebCorePreBuild.cmd, but we did not add the /d option to xcopy to only copy if the destination is older than the source. All other xcopy-ing done has this to avoid doing extra copying which results in extra compiling.
Created attachment 205331 [details] Patch
Comment on attachment 205331 [details] Patch r=me
Comment on attachment 205331 [details] Patch Clearing flags on attachment: 205331 Committed r151935: <http://trac.webkit.org/changeset/151935>
All reviewed patches have been landed. Closing bug.