Introduce previousPositionOf() for VisiblePosition

Source/core/editing/FrameSelection.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 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 650 matching lines @@
     // The difference between modifyExtendingRight and modifyExtendingForward is:
     // modifyExtendingForward always extends forward logically.
     // modifyExtendingRight behaves the same as modifyExtendingForward except for extending character or word,
     // it extends forward logically if the enclosing block is LTR direction,
     // but it extends backward logically if the enclosing block is RTL direction.
     switch (granularity) {
     case CharacterGranularity:
         if (directionOfEnclosingBlock() == LTR)
             pos = pos.next(CanSkipOverEditingBoundary);
         else
-            pos = pos.previous(CanSkipOverEditingBoundary);
+            pos = previousPositionOf(pos, CanSkipOverEditingBoundary);
         break;
     case WordGranularity:
         if (directionOfEnclosingBlock() == LTR)
             pos = nextWordPositionForPlatform(pos);
         else
             pos = previousWordPosition(pos);
         break;
     case LineBoundary:
         if (directionOfEnclosingBlock() == LTR)
             pos = modifyExtendingForward(granularity);
@@ skipping 142 matching lines @@
     VisiblePosition pos(m_selection.extent(), m_selection.affinity());
 
     // The difference between modifyExtendingLeft and modifyExtendingBackward is:
     // modifyExtendingBackward always extends backward logically.
     // modifyExtendingLeft behaves the same as modifyExtendingBackward except for extending character or word,
     // it extends backward logically if the enclosing block is LTR direction,
     // but it extends forward logically if the enclosing block is RTL direction.
     switch (granularity) {
     case CharacterGranularity:
         if (directionOfEnclosingBlock() == LTR)
-            pos = pos.previous(CanSkipOverEditingBoundary);
+            pos = previousPositionOf(pos, CanSkipOverEditingBoundary);
         else
             pos = pos.next(CanSkipOverEditingBoundary);
         break;
     case WordGranularity:
         if (directionOfEnclosingBlock() == LTR)
             pos = previousWordPosition(pos);
         else
             pos = nextWordPositionForPlatform(pos);
         break;
     case LineBoundary:
@@ skipping 18 matching lines @@
 VisiblePosition FrameSelection::modifyExtendingBackward(TextGranularity granularity)
 {
     VisiblePosition pos(m_selection.extent(), m_selection.affinity());
 
     // Extending a selection backward by word or character from just after a table selects
     // the table.  This "makes sense" from the user perspective, esp. when deleting.
     // It was done here instead of in VisiblePosition because we want VPs to iterate
     // over everything.
     switch (granularity) {
     case CharacterGranularity:
-        pos = pos.previous(CanSkipOverEditingBoundary);
+        pos = previousPositionOf(pos, CanSkipOverEditingBoundary);
         break;
     case WordGranularity:
         pos = previousWordPosition(pos);
         break;
     case SentenceGranularity:
         pos = previousSentencePosition(pos);
         break;
     case LineGranularity:
         pos = previousLinePosition(pos, lineDirectionPointForBlockDirectionNavigation(EXTENT));
         break;
@@ skipping 57 matching lines @@
 }
 
 VisiblePosition FrameSelection::modifyMovingBackward(TextGranularity granularity)
 {
     VisiblePosition pos;
     switch (granularity) {
     case CharacterGranularity:
         if (isRange())
             pos = VisiblePosition(m_selection.start(), m_selection.affinity());
         else
-            pos = VisiblePosition(m_selection.extent(), m_selection.affinity()).previous(CanSkipOverEditingBoundary);
+            pos = previousPositionOf(VisiblePosition(m_selection.extent(), m_selection.affinity()), CanSkipOverEditingBoundary);
         break;
     case WordGranularity:
         pos = previousWordPosition(VisiblePosition(m_selection.extent(), m_selection.affinity()));
         break;
     case SentenceGranularity:
         pos = previousSentencePosition(VisiblePosition(m_selection.extent(), m_selection.affinity()));
         break;
     case LineGranularity:
         pos = previousLinePosition(startForPlatform(), lineDirectionPointForBlockDirectionNavigation(START));
         break;
@@ skipping 1107 matching lines @@
 
 void showTree(const blink::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
     else
         fprintf(stderr, "Cannot showTree for (nil) FrameSelection.\n");
 }
 
 #endif