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

3 files changed, 8 insertions, 5 deletions

diff --git a/core/include/fxcrt/fx_arb.h b/core/include/fxcrt/fx_arb.h
index 4950f81716..a7b25c1877 100644
--- a/core/include/fxcrt/fx_arb.h
+++ b/core/include/fxcrt/fx_arb.h
@@ -16,5 +16,8 @@ public:
     virtual FX_BOOL			EndChar() = 0;
     virtual FX_INT32		GetBidiInfo(FX_INT32 &iStart, FX_INT32 &iCount) = 0;
     virtual void			Reset() = 0;
+
+protected:
+    ~IFX_BidiChar() { }
 };
 #endif
diff --git a/core/include/fxcrt/fx_basic.h b/core/include/fxcrt/fx_basic.h
index 98a540c455..62324f5b2a 100644
--- a/core/include/fxcrt/fx_basic.h
+++ b/core/include/fxcrt/fx_basic.h
@@ -240,7 +240,7 @@ class IFX_BufferArchive
 {
 public:
     IFX_BufferArchive(FX_STRSIZE size);
-
+    virtual ~IFX_BufferArchive() { }
 
     virtual void			Clear();
 
@@ -271,7 +271,7 @@ class CFX_FileBufferArchive : public IFX_BufferArchive, public CFX_Object
 {
 public:
     CFX_FileBufferArchive(FX_STRSIZE size = 32768);
-    ~CFX_FileBufferArchive();
+    ~CFX_FileBufferArchive() override;
     virtual void			Clear();
 
     FX_BOOL					AttachFile(IFX_StreamWrite *pFile, FX_BOOL bTakeover = FALSE);
@@ -1377,7 +1377,7 @@ protected:
 class IFX_Pause
 {
 public:
-
+    virtual ~IFX_Pause() { }
     virtual FX_BOOL	NeedToPauseNow() = 0;
 };
 class CFX_DataFilter : public CFX_Object
diff --git a/core/include/fxcrt/fx_stream.h b/core/include/fxcrt/fx_stream.h
index 8e298f7727..e54af579b6 100644
--- a/core/include/fxcrt/fx_stream.h
+++ b/core/include/fxcrt/fx_stream.h
@@ -65,7 +65,7 @@ FX_BOOL		FX_File_Move(FX_WSTR fileNameSrc, FX_WSTR fileNameDst);
 class IFX_StreamWrite
 {
 public:
-
+    virtual ~IFX_StreamWrite() { }
     virtual void		Release() = 0;
 
     virtual	FX_BOOL		WriteBlock(const void* pData, size_t size) = 0;
@@ -91,6 +91,7 @@ IFX_FileWrite* FX_CreateFileWrite(FX_LPCWSTR filename);
 class IFX_StreamRead
 {
 public:
+    virtual ~IFX_StreamRead() { }
 
     virtual void			Release() = 0;
 
@@ -103,7 +104,6 @@ public:
 class IFX_FileRead : IFX_StreamRead
 {
 public:
-
     virtual void			Release() = 0;
 
     virtual FX_FILESIZE		GetSize() = 0;