Oilpan: move Range object to the oilpan heap.

Source/core/editing/VisibleSelection.h

Index: Source/core/editing/VisibleSelection.h
diff --git a/Source/core/editing/VisibleSelection.h b/Source/core/editing/VisibleSelection.h
index 2b7bd2a7bbba191042de33dffc24985808dec59a..c14630c15d700258279bc14bf5c7d10716c4e681 100644
--- a/Source/core/editing/VisibleSelection.h
+++ b/Source/core/editing/VisibleSelection.h
@@ -93,12 +93,12 @@ public:
     bool expandUsingGranularity(TextGranularity granularity);
 
     // We don't yet support multi-range selections, so we only ever have one range to return.
-    PassRefPtr<Range> firstRange() const;
+    PassRefPtrWillBeRawPtr<Range> firstRange() const;
 
     // FIXME: Most callers probably don't want this function, but are using it
     // for historical reasons.  toNormalizedRange contracts the range around
     // text, and moves the caret upstream before returning the range.
-    PassRefPtr<Range> toNormalizedRange() const;
+    PassRefPtrWillBeRawPtr<Range> toNormalizedRange() const;
 
     Element* rootEditableElement() const;
     bool isContentEditable() const;