Split CPDF_Stream/CPDF_StreamAcc into separate files

core/include/fpdfapi/cpdf_object.h

Index: core/include/fpdfapi/cpdf_object.h
diff --git a/core/include/fpdfapi/cpdf_object.h b/core/include/fpdfapi/cpdf_object.h
index 2add5524a8e4926db2ac3474994b81061a68cae0..97499d140c6c33fc97ad532f9da18a1483e0b1e8 100644
--- a/core/include/fpdfapi/cpdf_object.h
+++ b/core/include/fpdfapi/cpdf_object.h
@@ -150,4 +150,12 @@ inline const CPDF_Reference* ToReference(const CPDF_Object* obj) {
   return obj ? obj->AsReference() : nullptr;
 }
 
+inline CPDF_Stream* ToStream(CPDF_Object* obj) {
+  return obj ? obj->AsStream() : nullptr;
+}
+
+inline const CPDF_Stream* ToStream(const CPDF_Object* obj) {
+  return obj ? obj->AsStream() : nullptr;
+}
+
 #endif  // CORE_INCLUDE_FPDFAPI_CPDF_OBJECT_H_