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 854233d82233ad48ccf94ada5423b33a32236e6e..ed11b8316bf79cb336dab9cc06d8cd91495bf4d6 100644
--- a/third_party/WebKit/Source/core/dom/Element.h
+++ b/third_party/WebKit/Source/core/dom/Element.h
@@ -654,6 +654,12 @@ private:
     PropertySetCSSStyleDeclaration* inlineStyleCSSOMWrapper();
     void setInlineStyleFromString(const AtomicString&);
 
+    // If the only inherited changes in the parent element are independent,
+    // these changes can be directly propagated to this element (the child).
+    // If these conditions are met, propagates the changes to the current style
+    // and returns the new style. Otherwise, returns null.
+    PassRefPtr<ComputedStyle> propagateInheritedProperties(StyleRecalcChange);
+
     StyleRecalcChange recalcOwnStyle(StyleRecalcChange);
     // TODO(nainar): Make this const ComputedStyle&.
     StyleRecalcChange buildLayoutTree(ComputedStyle&);