Improving direction-based selection strategy.

Source/core/editing/GranularityStrategy.h

 // Copyright 2015 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 GranularityStrategy_h
 #define GranularityStrategy_h
 
 #include "core/editing/SelectionStrategy.h"
 #include "core/editing/VisibleSelection.h"
 
 namespace blink {
 
 class GranularityStrategy {
 public:
     virtual ~GranularityStrategy();
     virtual SelectionStrategy GetType() const = 0;
     virtual void Clear() = 0;
 
     // Calculates and returns the new selection based on the updated user
     // selection extent |extentPosition| and the granularity strategy.
-    virtual VisibleSelection updateExtent(const VisiblePosition& extentPosition, const VisibleSelection&) = 0;
+    virtual VisibleSelection updateExtent(const IntPoint&, LocalFrame*) = 0;
 
 protected:
     GranularityStrategy();
 };
 
 // Always uses character granularity.
 class CharacterGranularityStrategy final : public GranularityStrategy {
 public:
     CharacterGranularityStrategy();
     ~CharacterGranularityStrategy() final;
 
     // GranularityStrategy:
     SelectionStrategy GetType() const final;
     void Clear() final;
-    VisibleSelection updateExtent(const VisiblePosition& extentPosition, const VisibleSelection&) final;
+    VisibleSelection updateExtent(const IntPoint&, LocalFrame*) final;
 };
 
 // "Expand by word, shrink by character" selection strategy.
 // Uses character granularity when selection is shrinking. If the selection is
 // expanding, granularity doesn't change until a word boundary is passed, after
 // which the granularity switches to "word".
 class DirectionGranularityStrategy final : public GranularityStrategy {
 public:
     DirectionGranularityStrategy();
     ~DirectionGranularityStrategy() final;
 
     // GranularityStrategy:
     SelectionStrategy GetType() const final;
     void Clear() final;
-    VisibleSelection updateExtent(const VisiblePosition&, const VisibleSelection&) final;
+    VisibleSelection updateExtent(const IntPoint&, LocalFrame*) final;
 
 private:
     enum class BoundAdjust {CurrentPosIfOnBound, NextBoundIfOnBound};
     enum class SearchDirection {SearchBackwards, SearchForward};
 
     // Returns the next word boundary starting from |pos|. |direction| specifies
     // the direction in which to search for the next bound. nextIfOnBound
     // controls whether |pos| or the next boundary is returned when |pos| is
     // located exactly on word boundary.
     VisiblePosition nextWordBound(const VisiblePosition& /*pos*/, SearchDirection /*direction*/, BoundAdjust /*nextIfOnBound*/);
 
     // Current selection granularity being used
     TextGranularity m_granularity;
     // Set to true if the selection was shrunk (without changing relative
     // base/extent order) as a result of the most recent updateExtent call.
     bool m_lastMoveShrunkSelection;
+    IntPoint m_extentPoint;
+    int m_offset;
 };
 
 } // namespace blink
 
 #endif // GranularityStrategy_h