pdfviewer: add doPage function, cet stream from Contents

experimental/PdfViewer/pdfparser/native/SkNativeParsedPDF.cpp

 #include "SkNativeParsedPDF.h"
 #include "SkPdfNativeTokenizer.h"
 #include "SkPdfBasics.h"
 #include "SkPdfObject.h"
 
 #include <stdio.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 
@@ skipping 385 matching lines @@
             // TODO(edisonn): verify that it is a page tree indeed
             fillPages((SkPdfPageTreeNodeDictionary*)obj);
         }
     }
 }
 
 int SkNativeParsedPDF::pages() const {
     return fPages.count();
 }
 
+SkPdfPageObjectDictionary* SkNativeParsedPDF::page(int page) {
+    SkASSERT(page >= 0 && page < fPages.count());
+    return fPages[page];
+}
+
+
 SkPdfResourceDictionary* SkNativeParsedPDF::pageResources(int page) {
+    SkASSERT(page >= 0 && page < fPages.count());
     return fPages[page]->Resources(this);
 }
 
 // TODO(edisonn): Partial implemented. Move the logics directly in the code generator for inheritable and default value?
 SkRect SkNativeParsedPDF::MediaBox(int page) {
     SkPdfPageObjectDictionary* current = fPages[page];
     while (!current->has_MediaBox() && current->has_Parent()) {
         current = (SkPdfPageObjectDictionary*)current->Parent(this);
     }
     if (current) {
@@ skipping 78 matching lines @@
 }
 
 // TODO(edisonn): fix infinite loop if ref to itself!
 // TODO(edisonn): perf, fix refs at load, and resolve will simply return fResolvedReference?
 SkPdfObject* SkNativeParsedPDF::resolveReference(const SkPdfObject* ref) {
     if (ref && ref->isReference()) {
         int id = ref->referenceId();
         // TODO(edisonn): generation/updates not supported now
         //int gen = ref->referenceGeneration();
 
-        SkASSERT(!(id < 0 || id > fObjects.count()));
-
         // TODO(edisonn): verify id and gen expected
         if (id < 0 || id >= fObjects.count()) {
             // TODO(edisonn): report error/warning
             return NULL;
         }
 
         if (fObjects[id].fResolvedReference != NULL) {
             return fObjects[id].fResolvedReference;
         }
 
@@ skipping 15 matching lines @@
     return (SkPdfObject*)ref;
 }
 
 size_t SkNativeParsedPDF::bytesUsed() const {
     return fAllocator->bytesUsed() +
            fContentLength +
            fObjects.count() * sizeof(PublicObjectEntry) +
            fPages.count() * sizeof(SkPdfPageObjectDictionary*) +
            sizeof(*this);
 }