pdfviewer: pass the page number, report failure if at least one render fails, and check that xref s…

experimental/PdfViewer/pdfparser/native/SkNativeParsedPDF.cpp

Index: experimental/PdfViewer/pdfparser/native/SkNativeParsedPDF.cpp
===================================================================
--- experimental/PdfViewer/pdfparser/native/SkNativeParsedPDF.cpp	(revision 10543)
+++ experimental/PdfViewer/pdfparser/native/SkNativeParsedPDF.cpp	(working copy)
@@ -225,8 +225,13 @@
 }
 
 const unsigned char* SkNativeParsedPDF::readCrossReferenceSection(const unsigned char* xrefStart, const unsigned char* trailerEnd) {
-    const unsigned char* current = ignoreLine(xrefStart, trailerEnd);  // TODO(edisonn): verify next keyord is "xref", use nextObject here
+    SkPdfObject xref;
+    const unsigned char* current = nextObject(0, xrefStart, trailerEnd, &xref, NULL, NULL);
 
+    if (!xref.isKeyword("xref")) {
+        return trailerEnd;
+    }
+
     SkPdfObject token;
     while (current < trailerEnd) {
         token.reset();