Oilpan: move Range object to the oilpan heap.

Source/core/editing/SurroundingText.h

 /*
  * Copyright (C) 2012 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 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef SurroundingText_h
 #define SurroundingText_h
 
+#include "platform/heap/Handle.h"
 #include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
 class Range;
 class VisiblePosition;
 
 class SurroundingText {
     WTF_MAKE_NONCOPYABLE(SurroundingText);
 public:
     SurroundingText(const VisiblePosition&, unsigned maxLength);
 
     String content() const;
     unsigned positionOffsetInContent() const;
 
-    PassRefPtr<Range> rangeFromContentOffsets(unsigned startOffsetInContent, unsigned endOffsetInContent);
+    PassRefPtrWillBeRawPtr<Range> rangeFromContentOffsets(unsigned startOffsetInContent, unsigned endOffsetInContent);
 
 private:
-    RefPtr<Range> m_contentRange;
+    RefPtrWillBePersistent<Range> m_contentRange;
     size_t m_positionOffsetInContent;
 };
 
 } // namespace WebCore
 
 #endif // SurroundingText_h