Make a bunch of JBig2 classes independent of CJBig2_Object.

core/src/fxcodec/jbig2/JBig2_ArithDecoder.h

Index: core/src/fxcodec/jbig2/JBig2_ArithDecoder.h
diff --git a/core/src/fxcodec/jbig2/JBig2_ArithDecoder.h b/core/src/fxcodec/jbig2/JBig2_ArithDecoder.h
index 02580149278dddc2e705db700c81676007f04b27..78a18e34e96ec089b53b40ee539d9acdafb475f7 100644
--- a/core/src/fxcodec/jbig2/JBig2_ArithDecoder.h
+++ b/core/src/fxcodec/jbig2/JBig2_ArithDecoder.h
@@ -9,13 +9,15 @@
 #include "JBig2_Define.h"
 #include "JBig2_BitStream.h"
 #include "JBig2_ArithQe.h"
-typedef struct {
+
+struct JBig2ArithCtx {
   unsigned int MPS;
   unsigned int I;
-} JBig2ArithCtx;
-class CJBig2_ArithDecoder : public CJBig2_Object {
+};
+
+class CJBig2_ArithDecoder {
  public:
-  CJBig2_ArithDecoder(CJBig2_BitStream* pStream);
+  explicit CJBig2_ArithDecoder(CJBig2_BitStream* pStream);
 
   ~CJBig2_ArithDecoder();
 
@@ -31,6 +33,7 @@ class CJBig2_ArithDecoder : public CJBig2_Object {
   unsigned int CT;
   CJBig2_BitStream* m_pStream;
 };
+
 inline CJBig2_ArithDecoder::CJBig2_ArithDecoder(CJBig2_BitStream* pStream) {
   m_pStream = pStream;
   INITDEC();