Give names to the shading types

core/include/fpdfapi/fpdf_resource.h

Index: core/include/fpdfapi/fpdf_resource.h
diff --git a/core/include/fpdfapi/fpdf_resource.h b/core/include/fpdfapi/fpdf_resource.h
index 9fe6e2b95f8f2bf190f9aef81df2d0944f796190..1194985067c78c0e4af2ab3c03040e1937084228 100644
--- a/core/include/fpdfapi/fpdf_resource.h
+++ b/core/include/fpdfapi/fpdf_resource.h
@@ -679,6 +679,18 @@ class CPDF_TilingPattern : public CPDF_Pattern {
 
   CPDF_Form* m_pForm;
 };
+
+typedef enum {
+  kInvalidShading = 0,
+  kFunctionBasedShading = 1,
+  kAxialShading = 2,
+  kRadialShading = 3,
+  kFreeFormGouraudTriangleMeshShading = 4,
+  kLatticeFormGouraudTriangleMeshShading = 5,
+  kCoonsPatchMeshShading = 6,
+  kTensorProductPatchMeshShading = 7
+} ShadingType;
+
 class CPDF_ShadingPattern : public CPDF_Pattern {
  public:
   CPDF_ShadingPattern(CPDF_Document* pDoc,
@@ -696,7 +708,7 @@ class CPDF_ShadingPattern : public CPDF_Pattern {
 
   FX_BOOL Reload();
 
-  int m_ShadingType;
+  ShadingType m_ShadingType;
 
   CPDF_ColorSpace* m_pCS;  // Still keep m_pCS as some CPDF_ColorSpace (name
                            // object) are not managed as counted objects. Refer