Move some code out of CPDF_NameTree::LookupNamedDest().

Move some of the code into GetNamedDestFromObject(), which will soon be
used in two places, once LookupNamedDest() splits in two. Along the way,
stop declaring variables inside if-statements, and rename variables to
stop using Hungarian notation.

Change-Id: I5eaacc00498363f0c2b867622048ea3caa92e2cc
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/69750
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fpdfdoc/cpdf_nametree.cpp b/core/fpdfdoc/cpdf_nametree.cpp
index 810faf6..0ff847b 100644
--- a/core/fpdfdoc/cpdf_nametree.cpp
+++ b/core/fpdfdoc/cpdf_nametree.cpp
@@ -296,6 +296,18 @@
   return nCount;
 }
 
+CPDF_Array* GetNamedDestFromObject(CPDF_Object* obj) {
+  if (!obj)
+    return nullptr;
+  CPDF_Array* array = obj->AsArray();
+  if (array)
+    return array;
+  CPDF_Dictionary* dict = obj->AsDictionary();
+  if (dict)
+    return dict->GetArrayFor("D");
+  return nullptr;
+}
+
 }  // namespace
 
 CPDF_NameTree::CPDF_NameTree(CPDF_Dictionary* pRoot) : m_pRoot(pRoot) {
@@ -459,11 +471,5 @@
       return nullptr;
     pValue = pDests->GetDirectObjectFor(name);
   }
-  if (!pValue)
-    return nullptr;
-  if (CPDF_Array* pArray = pValue->AsArray())
-    return pArray;
-  if (CPDF_Dictionary* pDict = pValue->AsDictionary())
-    return pDict->GetArrayFor("D");
-  return nullptr;
+  return GetNamedDestFromObject(pValue);
 }