Make code compile with clang_use_chrome_plugin (part I)

core/fpdfapi/fpdf_page/include/cpdf_imageobject.h

Index: core/fpdfapi/fpdf_page/include/cpdf_imageobject.h
diff --git a/core/fpdfapi/fpdf_page/include/cpdf_imageobject.h b/core/fpdfapi/fpdf_page/include/cpdf_imageobject.h
index 9b983cc05c953d93690df40f1dc51b27858f9794..1128d12f8bb6bdd0bfd95f0098c071bdd26d2af9 100644
--- a/core/fpdfapi/fpdf_page/include/cpdf_imageobject.h
+++ b/core/fpdfapi/fpdf_page/include/cpdf_imageobject.h
@@ -17,13 +17,13 @@ class CPDF_ImageObject : public CPDF_PageObject {
   CPDF_ImageObject();
   ~CPDF_ImageObject() override;
 
-  // CPDF_PageObject:
+  // CPDF_PageObject
   CPDF_ImageObject* Clone() const override;
-  Type GetType() const override { return IMAGE; };
+  Type GetType() const override;
   void Transform(const CFX_Matrix& matrix) override;
-  bool IsImage() const override { return true; };
-  CPDF_ImageObject* AsImage() override { return this; };
-  const CPDF_ImageObject* AsImage() const override { return this; };
+  bool IsImage() const override;
+  CPDF_ImageObject* AsImage() override;
+  const CPDF_ImageObject* AsImage() const override;
 
   void CalcBoundingBox();