The following test is failing on GTK since r233493-233495 (image only failure): fast/text/multiple-text-shadow-overflow-layout-rect.html The difference is very subtle (one line of pixels in a shadow)
My change seems the culprit. Sorry. https://trac.webkit.org/changeset/233495 Bug 187244
Created attachment 344310 [details] [screenshot] Safari doesn't clip fast/text/multiple-text-shadow-overflow-layout-rect.html is a ref test. -actual.png and -expect.png are clipped the upper part of the SVG font differently. https://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20(Tests)/r233495%20(7263)/fast/text/multiple-text-shadow-overflow-layout-rect-diffs.html In the first place, this test case is a test to check the SVG font isn't clipped as the comment in the test case states. I attached screenshot of Safari. It doesn't clip at all.
Chrome deprecated SVG font support. Other browsers don't plan to support it. https://caniuse.com/#feat=svg-fonts It seems that WebKit doesn't claims to support SVG fonts. https://webkit.org/status/#?search=font
Fixed and Unmarked in https://trac.webkit.org/changeset/233556/ . But, the clipping issue still remains.