Pass nextTextSibling to ::before layout rebuild.

third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 22 matching lines @@
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/StyleEngine.h"
 #include "core/dom/Text.h"
 #include "core/dom/shadow/ElementShadow.h"
 #include "core/dom/shadow/InsertionPoint.h"
 #include "core/dom/shadow/ShadowRootRareDataV0.h"
 #include "core/dom/shadow/SlotAssignment.h"
 #include "core/editing/serializers/Serialization.h"
 #include "core/html/HTMLShadowElement.h"
 #include "core/html/HTMLSlotElement.h"
+#include "core/layout/LayoutObject.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 struct SameSizeAsShadowRoot : public DocumentFragment, public TreeScope {
   char emptyClassFieldsDueToGCMixinMarker[1];
   Member<void*> willbeMember[3];
   unsigned countersAndFlags[1];
 };
 
@@ skipping 95 matching lines @@
       setNeedsReattachLayoutTree();
   }
 
   // There's no style to update so just calling recalcStyle means we're updated.
   clearNeedsStyleRecalc();
 
   recalcDescendantStyles(change);
   clearChildNeedsStyleRecalc();
 }
 
-void ShadowRoot::rebuildLayoutTree() {
+void ShadowRoot::rebuildLayoutTree(Text*& nextTextSibling) {
   // ShadowRoot doesn't support custom callbacks.
   DCHECK(!hasCustomStyleCallbacks());
 
+  if (!needsReattachLayoutTree() && !childNeedsReattachLayoutTree()) {
+    skipRebuildLayoutTree(nextTextSibling);
+    return;
+  }
+
   StyleSharingDepthScope sharingScope(*this);
 
   clearNeedsReattachLayoutTree();
-  rebuildChildrenLayoutTrees();
+  rebuildChildrenLayoutTrees(nextTextSibling);
   clearChildNeedsReattachLayoutTree();
 }
 
+void ShadowRoot::skipRebuildLayoutTree(Text*& nextTextSibling) const {
+  // We call this method when neither this, nor our child nodes are marked
+  // for re-attachment, but the host has been marked with
+  // childNeedsReattachLayoutTree. That happens when ::before or ::after needs
+  // re-attachment. In that case, we update nextTextSibling with the first text
+  // node sibling not preceeded by any in-flow children to allow for correct
+  // whitespace re-attachment if the ::before element display changes.
+  DCHECK(document().inStyleRecalc());
+  DCHECK(!document().childNeedsDistributionRecalc());
+  DCHECK(!needsStyleRecalc());
+  DCHECK(!childNeedsStyleRecalc());
+  DCHECK(!needsReattachLayoutTree());
+  DCHECK(!childNeedsReattachLayoutTree());
+
+  for (Node* sibling = firstChild(); sibling;
+       sibling = sibling->nextSibling()) {
+    if (sibling->isTextNode()) {
+      nextTextSibling = toText(sibling);
+      return;
+    }
+    LayoutObject* layoutObject = sibling->layoutObject();
+    if (layoutObject && !layoutObject->isFloatingOrOutOfFlowPositioned()) {
+      nextTextSibling = nullptr;
+      return;
+    }
+  }
+}
+
 void ShadowRoot::attachLayoutTree(const AttachContext& context) {
   StyleSharingDepthScope sharingScope(*this);
   DocumentFragment::attachLayoutTree(context);
 }
 
 void ShadowRoot::detachLayoutTree(const AttachContext& context) {
   if (context.clearInvalidation)
     document().styleEngine().styleInvalidator().clearInvalidation(*this);
   DocumentFragment::detachLayoutTree(context);
 }
@@ skipping 167 matching lines @@
       ostream << "ShadowRootType::Open";
       break;
     case ShadowRootType::Closed:
       ostream << "ShadowRootType::Closed";
       break;
   }
   return ostream;
 }
 
 }  // namespace blink