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

13 files changed, 44 insertions, 25 deletions

diff --git a/core/include/fpdfapi/fpdf_parser.h b/core/include/fpdfapi/fpdf_parser.h
index da22dc72ca..d2fdad4cfb 100644
--- a/core/include/fpdfapi/fpdf_parser.h
+++ b/core/include/fpdfapi/fpdf_parser.h
@@ -49,7 +49,7 @@ class CFX_PrivateData;
 class IPDF_EnumPageHandler
 {
 public:
-
+    virtual ~IPDF_EnumPageHandler() { }
     virtual FX_BOOL EnumPage(CPDF_Dictionary* pPageDict) = 0;
 };
 class CPDF_Document : public CFX_PrivateData, public CPDF_IndirectObjects
@@ -247,8 +247,7 @@ class CPDF_SyntaxParser : public CFX_Object
 public:
 
     CPDF_SyntaxParser();
-
-    ~CPDF_SyntaxParser();
+    virtual ~CPDF_SyntaxParser();
 
     void				InitParser(IFX_FileRead* pFileAccess, FX_DWORD HeaderOffset);
 
@@ -366,7 +365,7 @@ struct PARSE_CONTEXT {
 class IPDF_DocParser : public CFX_Object
 {
 public:
-
+    virtual ~IPDF_DocParser() { }
     virtual FX_DWORD	GetRootObjNum() = 0;
 
     virtual FX_DWORD	GetInfoObjNum() = 0;
@@ -402,8 +401,7 @@ class CPDF_Parser FX_FINAL : public IPDF_DocParser
 public:
 
     CPDF_Parser();
-
-    ~CPDF_Parser();
+    ~CPDF_Parser() override;
 
     FX_DWORD			StartParse(FX_LPCSTR filename, FX_BOOL bReParse = FALSE);
 
@@ -853,13 +851,13 @@ protected:
 class IFX_FileAvail
 {
 public:
-
+    virtual ~IFX_FileAvail() { }
     virtual FX_BOOL			IsDataAvail( FX_FILESIZE offset, FX_DWORD size) = 0;
 };
 class IFX_DownloadHints
 {
 public:
-
+    virtual ~IFX_DownloadHints() { }
     virtual void			AddSegment(FX_FILESIZE offset, FX_DWORD size) = 0;
 };
 #define PDF_IS_LINEARIZED			1
@@ -871,13 +869,12 @@ public:
 class IPDF_DataAvail
 {
 public:
+    virtual ~IPDF_DataAvail() { }
 
     virtual FX_BOOL			IsDocAvail(IFX_DownloadHints* pHints) = 0;
 
-
     virtual void			SetDocument(CPDF_Document* pDoc) = 0;
 
-
     virtual FX_BOOL			IsPageAvail(int iPage, IFX_DownloadHints* pHints) = 0;
 
     virtual FX_BOOL			IsLinearized() = 0;
diff --git a/core/include/fpdfapi/fpdf_render.h b/core/include/fpdfapi/fpdf_render.h
index c059bedb2b..e2801f61f2 100644
--- a/core/include/fpdfapi/fpdf_render.h
+++ b/core/include/fpdfapi/fpdf_render.h
@@ -138,7 +138,7 @@ protected:
 class IPDF_BackgroundDraw
 {
 public:
-
+    virtual ~IPDF_BackgroundDraw() { }
     virtual	void	OnDrawBackground(
         CFX_RenderDevice* pBitmapDevice,
         const CFX_AffineMatrix* pOriginal2Bitmap
diff --git a/core/include/fpdfdoc/fpdf_ap.h b/core/include/fpdfdoc/fpdf_ap.h
index 78f9676221..02bbf249c4 100644
--- a/core/include/fpdfdoc/fpdf_ap.h
+++ b/core/include/fpdfdoc/fpdf_ap.h
@@ -13,9 +13,8 @@
 class IPVT_FontMap
 {
 public:
-
+    virtual ~IPVT_FontMap() { }
     virtual CPDF_Font*						GetPDFFont(FX_INT32 nFontIndex) = 0;
-
     virtual CFX_ByteString					GetPDFFontAlias(FX_INT32 nFontIndex) = 0;
 };
 struct CPVT_Dash {
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;
 
diff --git a/core/include/fpdfdoc/fpdf_vt.h b/core/include/fpdfdoc/fpdf_vt.h
index 41025cbe2e..3e23c3a1a3 100644
--- a/core/include/fpdfdoc/fpdf_vt.h
+++ b/core/include/fpdfdoc/fpdf_vt.h
@@ -275,6 +275,7 @@ struct CPVT_Section {
 class IPDF_VariableText_Provider
 {
 public:
+    virtual ~IPDF_VariableText_Provider() { }
 
     virtual FX_INT32						GetCharWidth(FX_INT32 nFontIndex, FX_WORD word, FX_INT32 nWordStyle) = 0;
 
@@ -291,6 +292,7 @@ public:
 class IPDF_VariableText_Iterator
 {
 public:
+    virtual ~IPDF_VariableText_Iterator() { }
 
     virtual FX_BOOL							NextWord() = 0;
 
@@ -323,11 +325,9 @@ public:
 class IPDF_VariableText
 {
 public:
-
     static IPDF_VariableText*			NewVariableText();
 
     static void							DelVariableText(IPDF_VariableText* pVT);
-public:
 
     virtual IPDF_VariableText_Provider*		SetProvider(IPDF_VariableText_Provider * pProvider) = 0;
 
@@ -440,5 +440,8 @@ public:
     virtual FX_INT32						WordPlaceToWordIndex(const CPVT_WordPlace & place) const = 0;
 
     virtual CPVT_WordPlace					WordIndexToWordPlace(FX_INT32 index) const = 0;
+
+protected:
+    ~IPDF_VariableText() { }
 };
 #endif
diff --git a/core/include/fxcodec/fx_codec_provider.h b/core/include/fxcodec/fx_codec_provider.h
index a3ef396a27..53733e7b1d 100644
--- a/core/include/fxcodec/fx_codec_provider.h
+++ b/core/include/fxcodec/fx_codec_provider.h
@@ -9,7 +9,6 @@
 class IFX_JpegProvider
 {
 public:
-
     virtual void		Release() = 0;
 
     virtual void*		CreateDecoder(FX_LPCBYTE src_buf, FX_DWORD src_size, int width, int height, int nComps, FX_BOOL ColorTransform) = 0;
@@ -49,5 +48,8 @@ public:
 
 
     virtual FX_DWORD	GetAvailInput(void* pContext, FX_LPBYTE* avail_buf_ptr = NULL) = 0;
+
+protected:
+    ~IFX_JpegProvider() { }
 };
 #endif
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;
diff --git a/core/include/fxge/fpf.h b/core/include/fxge/fpf.h
index 99d9b7c999..28d028cfbb 100644
--- a/core/include/fxge/fpf.h
+++ b/core/include/fxge/fpf.h
@@ -12,6 +12,7 @@ class IFPF_Font;
 class IFPF_DeviceModule
 {
 public:
+    virtual ~IFPF_DeviceModule() { }
     virtual void				Destroy() = 0;
     virtual IFPF_FontMgr*		GetFontMgr() = 0;
 };
@@ -41,10 +42,14 @@ public:
     virtual FX_INT32		GetHeight() const = 0;
     virtual FX_INT32		GetItalicAngle() const = 0;
     virtual FX_DWORD		GetFontData(FX_DWORD dwTable, FX_LPBYTE pBuffer, FX_DWORD dwSize) = 0;
+
+protected:
+    ~IFPF_Font() { }
 };
 class IFPF_FontMgr
 {
 public:
+    virtual ~IFPF_FontMgr() { }
     virtual void			LoadSystemFonts() = 0;
     virtual void			LoadPrivateFont(IFX_FileRead* pFontFile) = 0;
     virtual void			LoadPrivateFont(FX_BSTR bsFileName) = 0;
diff --git a/core/include/fxge/fx_dib.h b/core/include/fxge/fx_dib.h
index d8a2003548..f7e435d966 100644
--- a/core/include/fxge/fx_dib.h
+++ b/core/include/fxge/fx_dib.h
@@ -402,16 +402,15 @@ protected:
 class IFX_ScanlineComposer
 {
 public:
+    virtual ~IFX_ScanlineComposer() { }
 
     virtual	void		ComposeScanline(int line, FX_LPCBYTE scanline, FX_LPCBYTE scan_extra_alpha = NULL) = 0;
 
-
     virtual FX_BOOL		SetInfo(int width, int height, FXDIB_Format src_format, FX_DWORD* pSrcPalette) = 0;
 };
 class CFX_ScanlineCompositor : public CFX_Object
 {
 public:
-
     CFX_ScanlineCompositor();
 
     ~CFX_ScanlineCompositor();
diff --git a/core/include/fxge/fx_font.h b/core/include/fxge/fx_font.h
index 52f8f30d8d..bf9bb40500 100644
--- a/core/include/fxge/fx_font.h
+++ b/core/include/fxge/fx_font.h
@@ -243,6 +243,7 @@ public:
 class IFX_FontEnumerator
 {
 public:
+    virtual ~IFX_FontEnumerator() { }
 
     virtual void		HitFont() = 0;
 
@@ -251,6 +252,7 @@ public:
 class IFX_AdditionalFontEnum
 {
 public:
+    virtual ~IFX_AdditionalFontEnum() { }
     virtual int  CountFiles() = 0;
     virtual IFX_FileStream* GetFontFile(int index) = 0;
 };
@@ -296,6 +298,7 @@ class IFX_SystemFontInfo : public CFX_Object
 public:
     static IFX_SystemFontInfo*	CreateDefault();
     virtual void		Release() = 0;
+
     virtual	FX_BOOL		EnumFontList(CFX_FontMapper* pMapper) = 0;
     virtual void*		MapFont(int weight, FX_BOOL bItalic, int charset, int pitch_family, FX_LPCSTR face, FX_BOOL& bExact) = 0;
     virtual void*		GetFont(FX_LPCSTR face) = 0;
@@ -311,6 +314,8 @@ public:
     {
         return NULL;
     }
+protected:
+    ~IFX_SystemFontInfo() { }
 };
 class CFX_FolderFontInfo : public IFX_SystemFontInfo
 {
@@ -423,6 +428,9 @@ class IFX_GSUBTable
 public:
     virtual void	Release() = 0;
     virtual FX_BOOL GetVerticalGlyph(FX_DWORD glyphnum, FX_DWORD* vglyphnum) = 0;
+
+protected:
+     ~IFX_GSUBTable() { }
 };
 IFX_GSUBTable* FXGE_CreateGSUBTable(CFX_Font* pFont);
 #endif
diff --git a/core/include/fxge/fx_ge.h b/core/include/fxge/fx_ge.h
index 82719ffda6..0c4bce8003 100644
--- a/core/include/fxge/fx_ge.h
+++ b/core/include/fxge/fx_ge.h
@@ -637,9 +637,11 @@ public:
 class IFX_PSOutput
 {
 public:
-
-    virtual void	OutputPS(FX_LPCSTR string, int len) = 0;
     virtual void  Release() = 0;
+    virtual void	OutputPS(FX_LPCSTR string, int len) = 0;
+
+protected:
+    ~IFX_PSOutput() { }
 };
 class CPSFont;
 class CFX_PSRenderer : public CFX_Object