Support display: contents for elements, first-line and first-letter pseudos.

third_party/WebKit/Source/core/svg/SVGElement.cpp

Index: third_party/WebKit/Source/core/svg/SVGElement.cpp
diff --git a/third_party/WebKit/Source/core/svg/SVGElement.cpp b/third_party/WebKit/Source/core/svg/SVGElement.cpp
index ca28a2c62aabbe6da3ad50231c4f87911506fcf2..d4bb0cbf745c0126c3fc33a1fdd979b5ff3b5bd3 100644
--- a/third_party/WebKit/Source/core/svg/SVGElement.cpp
+++ b/third_party/WebKit/Source/core/svg/SVGElement.cpp
@@ -1021,7 +1021,7 @@ PassRefPtr<ComputedStyle> SVGElement::customStyleForLayoutObject() {
   }
 
   return document().ensureStyleResolver().styleForElement(
-      correspondingElement(), style, DisallowStyleSharing);
+      correspondingElement(), style, style, DisallowStyleSharing);

[rune, 2017/01/27 13:09:23]

Is this correct? Can we get here for SVGSVGElement being a child of some
display:contents html element?

[emilio, 2017/01/27 22:13:15]

Note that style will only be non-null when the parent element has a layout
object, so I think this is correct (though somewhat suboptimal I guess).

[rune, 2017/02/06 22:40:44]

The display property applies to SVG elements, but with a special interpretation
[1]. It should be clarified what display:contents means for SVG. If
display:contents skips creating layout boxes for SVG as well, the code above is
wrong. Make some tests to see what happens with your implementation. It looks
like display:content for a USE parent will cause the layoutObject to be null for
that parent and cause strangeness here?

Would it be best to override layoutObjectIsNeeded() to return true for
display:contents for SVG elements for now?

[1] https://www.w3.org/TR/SVG/painting.html#DisplayProperty

[emilio, 2017/02/08 10:59:24]

Makes sense, will do.

 }
 
 MutableStylePropertySet* SVGElement::animatedSMILStyleProperties() const {