pdfviewer: add indexed rbg image support, enhanche caching(setData) for SkPdfObject

experimental/PdfViewer/SkPdfFont.h

 #ifndef __DEFINED__SkPdfFont
 #define __DEFINED__SkPdfFont
 
 #include "SkPdfHeaders_autogen.h"
 #include "SkPdfMapper_autogen.h"
 
 #include <map>
 #include <string>
 
 #include "SkTypeface.h"
@@ skipping 297 matching lines @@
     // TODO(edisonn): warning/report
     printf("Unknown CIDToGIDMap: %s\n", name);
 #endif
     return NULL;
 }
 CIDToGIDMap* fCidToGid;
 */
 
 class SkPdfType3Font : public SkPdfFont {
     struct Type3FontChar {
-        const SkPdfObject* fObj;
+        SkPdfObject* fObj;
         double fWidth;
     };
 
     SkPdfDictionary* fCharProcs;
     SkPdfEncodingDictionary* fEncodingDict;
     unsigned int fFirstChar;
     unsigned int fLastChar;
 
     SkRect fFontBBox;
     SkMatrix fFonMatrix;
@@ skipping 82 matching lines @@
                              SkDoubleToScalar(0.0));
         return fChars[ch - fFirstChar].fWidth;
     }
 
     virtual void afterWord(SkPaint* paint, SkMatrix* matrix) {
 
     }
 };
 
 #endif  // __DEFINED__SkPdfFont