[Squad] Split out method for inline box style for pseudo elements.

We create an unobservable inline box for display:contents pseudo
elements storing the original style on the element. Split this code out
into a separate method as we will need it for constructing pseudo
elements as part of style recalc later.

Bug: 836126
Change-Id: I8610ea5cd92ebbefd0428f84ca2ff4e48169b232
Reviewed-on: https://chromium-review.googlesource.com/1109827Reviewed-by: Anders Ruud <andruud@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569264}

third_party/blink/renderer/core/dom/pseudo_element.cc

@@ -109,6 +109,11 @@ scoped_refptr<ComputedStyle> PseudoElement::CustomStyleForLayoutObject() {
   if (!original_style || original_style->Display() != EDisplay::kContents)
     return original_style;
 
+  return StoreOriginalAndReturnLayoutStyle(std::move(original_style));
+}
+
+scoped_refptr<ComputedStyle> PseudoElement::StoreOriginalAndReturnLayoutStyle(
+    scoped_refptr<ComputedStyle> original_style) {
   // For display:contents we should not generate a box, but we generate a non-
   // observable inline box for pseudo elements to be able to locate the
   // anonymous layout objects for generated content during DetachLayoutTree().
@@ -120,7 +125,7 @@ scoped_refptr<ComputedStyle> PseudoElement::CustomStyleForLayoutObject() {
 
   // Store the actual ComputedStyle to be able to return the correct values from
   // getComputedStyle().
-  StoreNonLayoutObjectComputedStyle(original_style);
+  StoreNonLayoutObjectComputedStyle(std::move(original_style));
   return layout_style;
 }
 

third_party/blink/renderer/core/dom/pseudo_element.h

@@ -47,6 +47,8 @@ class CORE_EXPORT PseudoElement : public Element {
   PseudoId GetPseudoId() const override { return pseudo_id_; }
   const ComputedStyle* VirtualEnsureComputedStyle(
       PseudoId pseudo_element_specifier = kPseudoIdNone) final;
+  scoped_refptr<ComputedStyle> StoreOriginalAndReturnLayoutStyle(
+      scoped_refptr<ComputedStyle>);
 
   static String PseudoElementNameForEvents(PseudoId);