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

Source/core/editing/VisibleUnits.cpp

Index: Source/core/editing/VisibleUnits.cpp
diff --git a/Source/core/editing/VisibleUnits.cpp b/Source/core/editing/VisibleUnits.cpp
index fac20284ca2038f8f6218fba055432348cf62a63..fc4c3a56b149a0a5dd7149fdb7c0b3dc2ed5b28f 100644
--- a/Source/core/editing/VisibleUnits.cpp
+++ b/Source/core/editing/VisibleUnits.cpp
@@ -454,6 +454,8 @@ static VisiblePosition previousBoundary(const VisiblePosition& c, BoundarySearch
     if (!boundary)
         return VisiblePosition();
 
+    TemporaryRangeScope scope;
+
     Document& d = boundary->document();
     Position start = createLegacyEditingPosition(boundary, 0).parentAnchoredEquivalent();
     Position end = pos.parentAnchoredEquivalent();
@@ -535,6 +537,8 @@ static VisiblePosition nextBoundary(const VisiblePosition& c, BoundarySearchFunc
     if (!boundary)
         return VisiblePosition();
 
+    TemporaryRangeScope scope;
+
     Document& d = boundary->document();
     RefPtrWillBeRawPtr<Range> searchRange(d.createRange());
     Position start(pos.parentAnchoredEquivalent());