Oilpan: Introduce TempRangeScope to avoid needless Range attaches on Document.

Source/core/editing/VisibleUnits.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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 436 matching lines @@
 
 typedef unsigned (*BoundarySearchFunction)(const UChar*, unsigned length, unsigned offset, BoundarySearchContextAvailability, bool& needMoreContext);
 
 static VisiblePosition previousBoundary(const VisiblePosition& c, BoundarySearchFunction searchFunction)
 {
     Position pos = c.deepEquivalent();
     Node* boundary = pos.parentEditingBoundary();
     if (!boundary)
         return VisiblePosition();
 
+    TempRangeScope scope;
+
     Document& d = boundary->document();
     Position start = createLegacyEditingPosition(boundary, 0).parentAnchoredEquivalent();
     Position end = pos.parentAnchoredEquivalent();
     RefPtrWillBeRawPtr<Range> searchRange = Range::create(d);
 
     Vector<UChar, 1024> string;
     unsigned suffixLength = 0;
 
     TrackExceptionState exceptionState;
     if (requiresContextForWordBoundary(c.characterBefore())) {
@@ skipping 61 matching lines @@
     return VisiblePosition(charIt.range()->endPosition(), DOWNSTREAM);
 }
 
 static VisiblePosition nextBoundary(const VisiblePosition& c, BoundarySearchFunction searchFunction)
 {
     Position pos = c.deepEquivalent();
     Node* boundary = pos.parentEditingBoundary();
     if (!boundary)
         return VisiblePosition();
 
+    TempRangeScope scope;
+
     Document& d = boundary->document();
     RefPtrWillBeRawPtr<Range> searchRange(d.createRange());
     Position start(pos.parentAnchoredEquivalent());
 
     Vector<UChar, 1024> string;
     unsigned prefixLength = 0;
 
     if (requiresContextForWordBoundary(c.characterAfter())) {
         RefPtrWillBeRawPtr<Range> backwardsScanRange(d.createRange());
         backwardsScanRange->setEnd(start.deprecatedNode(), start.deprecatedEditingOffset(), IGNORE_EXCEPTION);
@@ skipping 838 matching lines @@
 {
     return direction == LTR ? logicalStartOfLine(c) : logicalEndOfLine(c);
 }
 
 VisiblePosition rightBoundaryOfLine(const VisiblePosition& c, TextDirection direction)
 {
     return direction == LTR ? logicalEndOfLine(c) : logicalStartOfLine(c);
 }
 
 }