Remove PageObject's m_Type and add As<Type> functions

core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp

Index: core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
index ef0344cda0352fb2f23a4c49e7645311724df3d7..77c58f09255da975079c27f342564dc365cb2cac 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
@@ -31,10 +31,10 @@ void CPDF_PageContentGenerator::GenerateContent() {
   CPDF_Dictionary* pPageDict = m_pPage->m_pFormDict;
   for (int i = 0; i < m_pageObjects.GetSize(); ++i) {
     CPDF_PageObject* pPageObj = m_pageObjects[i];
-    if (!pPageObj || pPageObj->m_Type != CPDF_PageObject::IMAGE) {
+    if (!pPageObj || !pPageObj->IsImage()) {
       continue;
     }
-    ProcessImage(buf, (CPDF_ImageObject*)pPageObj);
+    ProcessImage(buf, pPageObj->AsImage());
   }
   CPDF_Object* pContent =
       pPageDict ? pPageDict->GetElementValue("Contents") : NULL;