Fix -Wnon-virtual-dtor compiler warnings.

This is done by explicitly adding a virtual dtor to interface classes,
since the cost is small given that there are already virtual functions.

The exceptions are for classes that have a Release() or Delete() method,
in which case it is non-virtual and protected to indicate that the virtual
class is never the deletion point.

BUG=
R=brucedawson@chromium.org, thestig@chromium.org

Review URL: https://codereview.chromium.org/810883005

1 files changed, 1 insertions, 0 deletions

diff --git a/core/include/fpdfdoc/fpdf_tagged.h b/core/include/fpdfdoc/fpdf_tagged.h
index f3ab01ea28..1a2a5d4ffa 100644
--- a/core/include/fpdfdoc/fpdf_tagged.h
+++ b/core/include/fpdfdoc/fpdf_tagged.h
@@ -68,6 +68,7 @@ struct CPDF_StructKid {
 class CPDF_StructElement : public CFX_Object
 {
 public:
+    virtual ~CPDF_StructElement() { }
 
     virtual CPDF_StructTree*	GetTree() const = 0;