Oilpan: Prepare to move SQLError to oilpan heap.

Source/modules/webdatabase/SQLStatementBackend.h

Index: Source/modules/webdatabase/SQLStatementBackend.h
diff --git a/Source/modules/webdatabase/SQLStatementBackend.h b/Source/modules/webdatabase/SQLStatementBackend.h
index b5aed9703f6864324b31808cd670409752515b71..fc6e20208d20f78132b6f3b8de5a7d04ee7a7fa4 100644
--- a/Source/modules/webdatabase/SQLStatementBackend.h
+++ b/Source/modules/webdatabase/SQLStatementBackend.h
@@ -39,7 +39,7 @@ namespace WebCore {
 
 class AbstractSQLStatement;
 class DatabaseBackend;
-class SQLError;
+class SQLErrorData;
 class SQLTransactionBackend;
 
 class SQLStatementBackend FINAL : public AbstractSQLStatementBackend {
@@ -57,7 +57,7 @@ public:
     void setVersionMismatchedError(DatabaseBackend*);
 
     AbstractSQLStatement* frontend();
-    virtual PassRefPtr<SQLError> sqlError() const OVERRIDE;
+    virtual SQLErrorData* sqlError() const OVERRIDE;
     virtual SQLResultSet* sqlResultSet() const OVERRIDE;
 
 private:
@@ -73,7 +73,7 @@ private:
     bool m_hasCallback;
     bool m_hasErrorCallback;
 
-    RefPtr<SQLError> m_error;
+    OwnPtr<SQLErrorData> m_error;
     RefPtrWillBeMember<SQLResultSet> m_resultSet;
 
     int m_permissions;