Make code compile with clang_use_chrome_plugin (part I)

core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp

Index: core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp
diff --git a/core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp b/core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp
index de84f298650df2ecdaba93ee2fd702e8f18b546c..b2eb5e642c34a44631ae95b64c8b673ef3c54e97 100644
--- a/core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp
@@ -30,6 +30,10 @@ CPDF_ShadingObject* CPDF_ShadingObject::Clone() const {
   return obj;
 }
 
+CPDF_PageObject::Type CPDF_ShadingObject::GetType() const {
+  return SHADING;
+}
+
 void CPDF_ShadingObject::Transform(const CFX_Matrix& matrix) {
   if (!m_ClipPath.IsNull()) {
     m_ClipPath.GetModify();
@@ -43,6 +47,18 @@ void CPDF_ShadingObject::Transform(const CFX_Matrix& matrix) {
   }
 }
 
+bool CPDF_ShadingObject::IsShading() const {
+  return true;
+}
+
+CPDF_ShadingObject* CPDF_ShadingObject::AsShading() {
+  return this;
+}
+
+const CPDF_ShadingObject* CPDF_ShadingObject::AsShading() const {
+  return this;
+}
+
 void CPDF_ShadingObject::CalcBoundingBox() {
   if (m_ClipPath.IsNull()) {
     return;