Get rid of redundant layout tree update related to selection

third_party/WebKit/Source/core/editing/SelectionTemplate.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 SelectionTemplate_h
 #define SelectionTemplate_h
 
+#include <iosfwd>
 #include "base/macros.h"
 #include "core/CoreExport.h"
 #include "core/editing/EphemeralRange.h"
 #include "core/editing/Position.h"
 #include "core/editing/PositionWithAffinity.h"
+#include "core/editing/SelectionType.h"
 #include "core/editing/TextAffinity.h"
 #include "core/editing/TextGranularity.h"
 #include "wtf/Allocator.h"
-#include <iosfwd>
 
 namespace blink {
 
 // SelectionTemplate is used for representing a selection in DOM tree or Flat
 // tree with template parameter |Strategy|. Instances of |SelectionTemplate|
 // are immutable objects, you can't change them once constructed.
 //
 // To construct |SelectionTemplate| object, please use |Builder| class.
 template <typename Strategy>
 class CORE_EXPORT SelectionTemplate final {
@@ skipping 53 matching lines @@
   SelectionTemplate& operator=(const SelectionTemplate&) = default;
 
   bool operator==(const SelectionTemplate&) const;
   bool operator!=(const SelectionTemplate&) const;
 
   const PositionTemplate<Strategy>& base() const;
   const PositionTemplate<Strategy>& extent() const;
   TextAffinity affinity() const { return m_affinity; }
   TextGranularity granularity() const { return m_granularity; }
   bool hasTrailingWhitespace() const { return m_hasTrailingWhitespace; }
+  bool isCaret() const { return m_base.isNotNull() && m_base == m_extent; }
   bool isDirectional() const { return m_isDirectional; }
   bool isHandleVisible() const { return m_isHandleVisible; }
   bool isNone() const { return m_base.isNull(); }
+  bool isRange() const { return m_base != m_extent; }
 
   // Returns true if |this| selection holds valid values otherwise it causes
   // assertion failure.
   bool assertValid() const;
   bool assertValidFor(const Document&) const;
 
+  const PositionTemplate<Strategy>& computeEndPosition() const;
+  const PositionTemplate<Strategy>& computeStartPosition() const;
+  SelectionType computeSelectionTypeConsideringGranularity() const;
+
   DECLARE_TRACE();
 
   void printTo(std::ostream*, const char* type) const;
 #ifndef NDEBUG
   void showTreeForThis() const;
 #endif
 
  private:
   friend class SelectionEditor;
 
@@ skipping 18 matching lines @@
 
 using SelectionInDOMTree = SelectionTemplate<EditingStrategy>;
 using SelectionInFlatTree = SelectionTemplate<EditingInFlatTreeStrategy>;
 
 CORE_EXPORT std::ostream& operator<<(std::ostream&, const SelectionInDOMTree&);
 CORE_EXPORT std::ostream& operator<<(std::ostream&, const SelectionInFlatTree&);
 
 }  // namespace blink
 
 #endif  // SelectionTemplate_h