Make SynchronousMutationObserver::didMergeTextNodes() to take both merged and merging nodes

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SynchronousMutationObserver_h
 #define SynchronousMutationObserver_h
 
 #include "base/macros.h"
 #include "core/CoreExport.h"
 #include "platform/LifecycleObserver.h"
 
 namespace blink {
 
 class CharacterData;
 class ContainerNode;
 class Document;
+class NodeWithIndex;
 class Text;
 
 // This class is a base class for classes which observe DOM tree mutation
 // synchronously. If you want to observe DOM tree mutation asynchronously see
 // MutationObserver Web API.
 //
 // TODO(yosin): Following classes should be derived from this class to
 // simplify Document class.
 //  - DragCaretController
 //  - DocumentMarkerController
 //  - EventHandler
 //  - FrameCaret
 //  - InputMethodController
 //  - SelectionController
 //  - Range set
 //  - NodeIterator set
 class CORE_EXPORT SynchronousMutationObserver
     : public LifecycleObserver<Document, SynchronousMutationObserver> {
  public:
   // TODO(yosin): We will have following member functions:
   //  - dataWillBeChanged(const CharacterData&);
   //  - didMoveTreeToNewDocument(const Node& root);
   //  - didInsertText(Node*, unsigned offset, unsigned length);
   //  - didRemoveText(Node*, unsigned offset, unsigned length);
 
   // Called after child nodes changed.
   virtual void didChangeChildren(const ContainerNode&);
 
-  // TODO(yosin): We should use |const Text& oldNode|.
-  // Called after characters in |oldNode| is appended at |offset| in
-  // |oldNdoe->previousSibling()|.
-  virtual void didMergeTextNodes(Text& oldNode, unsigned offset);
+  // Called after characters in |nodeToBeRemoved| is appended into |mergedNode|.
+  // |oldLength| holds length of |mergedNode| before merge.
+  virtual void didMergeTextNodes(const Text& mergedNode,
+                                 const NodeWithIndex& nodeToBeRemovedWithIndex,
+                                 unsigned oldLength);
 
   // Called just after node tree |root| is moved to new document.
   virtual void didMoveTreeToNewDocument(const Node& root);
 
   // Called when |Text| node is split, next sibling |oldNode| contains
   // characters after split point.
   virtual void didSplitTextNode(const Text& oldNode);
 
   // Called when |CharacterData| is updated at |offset|, |oldLength| is a
   // number of deleted character and |newLength| is a number of added
@@ skipping 15 matching lines @@
  protected:
   SynchronousMutationObserver();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SynchronousMutationObserver);
 };
 
 }  // namespace blink
 
 #endif  // SynchronousMutationObserver_h