pdfviewer: fix warnings on mac

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 333 matching lines @@
         }
 
         // null?
         fCharProcs = dict->CharProcs(parsed);
 
         fToUnicode = NULL;
         if (dict->has_ToUnicode()) {
             fToUnicode = new SkPdfToUnicode(parsed, dict->ToUnicode(parsed));
         }
 
-        fFirstChar = dict->FirstChar(parsed);
-        fLastChar = dict->LastChar(parsed);
+        fFirstChar = (unsigned int)dict->FirstChar(parsed);
+        fLastChar = (unsigned int)dict->LastChar(parsed);
         fFonMatrix = dict->has_FontMatrix() ? dict->FontMatrix(parsed) : SkMatrix::I();
 
         if (dict->has_FontBBox()) {
             fFontBBox = dict->FontBBox(parsed);
         }
 
         fChars = new Type3FontChar[fLastChar - fFirstChar + 1];
 
         memset(fChars, 0, sizeof(fChars[0]) * (fLastChar - fFirstChar + 1));
 
 
         const SkPdfArray* widths = dict->Widths(parsed);
         for (unsigned int i = 0 ; i < widths->size(); i++) {
             if ((fFirstChar + i) < fFirstChar || (fFirstChar + i) > fLastChar) {
                 printf("break; error 1\n");
             }
             fChars[i].fWidth = (*widths)[i]->numberValue();
         }
 
         const SkPdfArray* diffs = fEncodingDict->Differences(parsed);
         unsigned int j = fFirstChar;
         for (unsigned int i = 0 ; i < diffs->size(); i++) {
             if ((*diffs)[i]->isInteger()) {
-                j = (*diffs)[i]->intValue();
+                j = (unsigned int)(*diffs)[i]->intValue();
             } else if ((*diffs)[i]->isName()) {
                 if (j < fFirstChar || j > fLastChar) {
                     printf("break; error 2\n");
                 }
                 fChars[j - fFirstChar].fObj = fCharProcs->get((*diffs)[i]->nameValue());
                 j++;
             } else {
                 // err
             }
         }
@@ skipping 20 matching lines @@
                              SkDoubleToScalar(0.0));
         return fChars[ch - fFirstChar].fWidth;
     }
 
     virtual void afterWord(SkPaint* paint, SkMatrix* matrix) {
 
     }
 };
 
 #endif  // __DEFINED__SkPdfFont