Keep formatting tags included when it is cut or copied.

third_party/WebKit/Source/core/editing/EditingUtilities.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1118 matching lines @@
 bool isHTMLListElement(Node* n)
 {
     return (n && (isHTMLUListElement(*n) || isHTMLOListElement(*n) || isHTMLDListElement(*n)));
 }
 
 bool isListItem(const Node* n)
 {
     return n && n->layoutObject() && n->layoutObject()->isListItem();
 }
 
+bool isPresentationalHTMLElement(const Node* node)
+{
+    if (!node->isHTMLElement())
+        return false;
+
+    const HTMLElement& element = toHTMLElement(*node);
+    return element.hasTagName(uTag) || element.hasTagName(sTag) || element.hasTagName(strikeTag)
+        || element.hasTagName(iTag) || element.hasTagName(emTag) || element.hasTagName(bTag) || element.hasTagName(strongTag);
+}
+
 Element* associatedElementOf(const Position& position)
 {
     Node* node = position.anchorNode();
     if (!node || node->isElementNode())
         return toElement(node);
     ContainerNode* parent = NodeTraversal::parent(*node);
     return parent && parent->isElementNode() ? toElement(parent) : nullptr;
 }
 
 Element* enclosingElementWithTag(const Position& p, const QualifiedName& tagName)
@@ skipping 739 matching lines @@
             return InputType::DeleteWordBackward;
         if (granularity == LineBoundary)
             return InputType::DeleteLineBackward;
         return InputType::DeleteContentBackward;
     default:
         return InputType::None;
     }
 }
 
 } // namespace blink