Add a fast-path for independent inherited properties

third_party/WebKit/Source/core/dom/Element.h

Index: third_party/WebKit/Source/core/dom/Element.h
diff --git a/third_party/WebKit/Source/core/dom/Element.h b/third_party/WebKit/Source/core/dom/Element.h
index 1f21fcaf2f4483149f863d350b5fef51daa3857b..35d5f558b8177b3e9950db0ab37e0d506c51eede 100644
--- a/third_party/WebKit/Source/core/dom/Element.h
+++ b/third_party/WebKit/Source/core/dom/Element.h
@@ -649,6 +649,10 @@ private:
     PropertySetCSSStyleDeclaration* inlineStyleCSSOMWrapper();
     void setInlineStyleFromString(const AtomicString&);
 
+    // Returns whether the parent contains independent-only inherited changes
+    // that can be directly propagated to the child.

[meade_UTC10, 2016/07/13 07:29:13]

I found this a little hard to understand - "the child" is this element right?

And this is checking whether the only changed properties are independent (and
thus whether a full style recalc is required)?

[sashab, 2016/07/14 05:08:41]

Yup :) clarified the comment.

+    bool canPropagateInheritedProperties(StyleRecalcChange);
+
     StyleRecalcChange recalcOwnStyle(StyleRecalcChange);
     // TODO(nainar): Make this const ComputedStyle&.
     StyleRecalcChange buildOwnLayout(ComputedStyle&);