With the attached test file --- <!DOCTYPE HTML> <title>intrinsic width of text-indent on blocks</title> <style> body { font-size: 10px } div { float: left; clear: left; margin: 0 0 1px 0; background: blue; color: white; height: 5px } span { display: inline-block; width: 10px } </style> <div style="text-indent: 50%"><span></span></div> ---- WebKit's behaviour differs to Moz and Opera (Moz and Opera agree). WebKit renders the div at 50% of the client width. Moz and Opera render it as 10px wide. Note: this test was reduced from a Mozilla test case for CSS3 calc() (http://mxr.mozilla.org/mozilla-central/source/layout/reftests/w3c-css/submitted/values3/calc-text-indent-intrinsic-1.html?force=1). Credit to David Baron for the original test.
Created attachment 183713 [details] test file
Safari, Chrome, and Firefox all agree on rendering for this test case. I don't believe there is any remaining compatibility issue.