Add DocumentMarkerList in preparation for DocumentMarkerController refactor

third_party/WebKit/Source/core/editing/markers/DocumentMarker.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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 148 matching lines @@
       m_details(TextCompositionMarkerDetails::create(underlineColor,
                                                      thick,
                                                      backgroundColor)) {}
 
 DocumentMarker::DocumentMarker(const DocumentMarker& marker)
     : m_type(marker.type()),
       m_startOffset(marker.startOffset()),
       m_endOffset(marker.endOffset()),
       m_details(marker.details()) {}
 
+DocumentMarker::ShiftMarkerResult DocumentMarker::getShiftedMarkerPosition(

[Xiaocheng, 2017/03/29 19:41:43]

nit: I think the previous patch should directly implement this function in
DocumentMarker, so that we don't need to move it in this patch.

It also makes it easy to compare the behavior change.

+    unsigned offset,
+    unsigned oldLength,
+    unsigned newLength) const {
+  ShiftMarkerResult result;
+  result.newStartOffset = startOffset();
+  result.newEndOffset = endOffset();
+  result.shouldRemoveMarker = false;
+
+  // algorithm inspired by https://dom.spec.whatwg.org/#concept-cd-replace
+  // but with some changes
+
+  // Deviation from the concept-cd-replace algorithm: second condition in the
+  // next line (don't include text inserted immediately before a marker in the
+  // marked range, but do include the new text if it's replacing text in the
+  // marked range)
+  if (startOffset() > offset || (startOffset() == offset && oldLength == 0)) {
+    if (startOffset() <= offset + oldLength) {
+      // Marker start was in the replaced text. Move to end of new text
+      // (Deviation from the concept-cd-replace algorithm: that algorithm
+      // would move to the beginning of the new text here)
+      result.newStartOffset = offset + newLength;
+    } else {
+      // Marker start was after the replaced text. Shift by length
+      // difference
+      result.newStartOffset = startOffset() + newLength - oldLength;
+    }
+  }
+
+  if (endOffset() > offset) {
+    // Deviation from the concept-cd-replace algorithm: < instead of <= in
+    // the next line
+    if (endOffset() < offset + oldLength) {
+      // Marker end was in the replaced text. Move to beginning of new text
+      result.newEndOffset = offset;
+    } else {
+      // Marker end was after the replaced text. Shift by length difference
+      result.newEndOffset = endOffset() + newLength - oldLength;
+    }
+  }
+
+  if (result.newStartOffset >= result.newEndOffset)
+    result.shouldRemoveMarker = true;
+
+  return result;
+}
+
 void DocumentMarker::shiftOffsets(int delta) {
   m_startOffset += delta;
   m_endOffset += delta;
 }
 
 void DocumentMarker::setActiveMatch(bool active) {
   m_details = DocumentMarkerTextMatch::create(active);
 }
 
 const String& DocumentMarker::description() const {
@@ skipping 29 matching lines @@
           toTextCompositionMarkerDetails(m_details.get()))
     return details->backgroundColor();
   return Color::transparent;
 }
 
 DEFINE_TRACE(DocumentMarker) {
   visitor->trace(m_details);
 }
 
 }  // namespace blink