Make Document::styleForElementIgnoringPendingStyleSheets() be aware of a flat tree structure

third_party/WebKit/LayoutTests/fast/dom/shadow/distribution-update-recalcs-style.html

Index: third_party/WebKit/LayoutTests/fast/dom/shadow/distribution-update-recalcs-style.html
diff --git a/third_party/WebKit/LayoutTests/fast/dom/shadow/distribution-update-recalcs-style.html b/third_party/WebKit/LayoutTests/fast/dom/shadow/distribution-update-recalcs-style.html
index 98283417d778e0ffa4bccb41b3e0e054dd3aa60c..cbb0eabd85d18510874650dd5e11f83455e156f8 100644
--- a/third_party/WebKit/LayoutTests/fast/dom/shadow/distribution-update-recalcs-style.html
+++ b/third_party/WebKit/LayoutTests/fast/dom/shadow/distribution-update-recalcs-style.html
@@ -28,10 +28,10 @@ var sr = document.getElementById("host").createShadowRoot();
 sr.innerHTML = '<style>div { color: blue }</style><div><content id="contentId" select="#div-child"></content></div>';
 
 shouldBe('getColorProperty("div-child")', '"rgb(0, 0, 255)"');
-shouldBe('getColorProperty("span-child")', '"rgb(255, 0, 0)"');

[hayato, 2016/08/23 11:50:26]

This is a bug of the original test, which should be updated.

[rune, 2016/08/23 12:36:12]

Is there a spec which talks about inheritance for unassigned nodes? I'm not able
to find anything.

[hayato, 2016/08/24 03:34:58]

Good point.

http://w3c.github.io/webcomponents/spec/shadow/#flattening-algorithm should
determine the *parent* in CSS inheritance.
(The algorithm has been upstreamed to CSS Scoping:
https://drafts.csswg.org/css-scoping/#flattening)

For a host's child which is not assigned to any slot, I think there is no parent
for that.

[rune, 2016/08/24 12:38:44]

Then shouldn't it return the empty string for computed style like we do for
nodes in detached subtrees? There was a discussion about the existence of
computed style of detached trees on www-style in May. Don't think there was a
conclusion for that issue, though.

+shouldBe('getColorProperty("span-child")', '"rgb(0, 0, 0)"');
 
 sr.getElementById("contentId").select = "#span-child";
-shouldBe('getColorProperty("div-child")', '"rgb(255, 0, 0)"');
+shouldBe('getColorProperty("div-child")', '"rgb(0, 0, 0)"');
 shouldBe('getColorProperty("span-child")', '"rgb(0, 0, 255)"');
 
 if (window.testRunner)