Implement FPDF_VIEWERREF_GetName() API.

core/fpdfdoc/cpdf_viewerpreferences.h

Index: core/fpdfdoc/cpdf_viewerpreferences.h
diff --git a/core/fpdfdoc/cpdf_viewerpreferences.h b/core/fpdfdoc/cpdf_viewerpreferences.h
index c64292d9f91314fd73a56888b193f287ec2a5c72..c7e9112380d6b685fc6a454ac0d31ed6bcb0b893 100644
--- a/core/fpdfdoc/cpdf_viewerpreferences.h
+++ b/core/fpdfdoc/cpdf_viewerpreferences.h
@@ -25,6 +25,11 @@ class CPDF_ViewerPreferences {
   CPDF_Array* PrintPageRange() const;
   CFX_ByteString Duplex() const;
 
+  // Gets the entry for |bsKey|. If the entry exists and it is of type name,
+  // then this method writes the value into |bsVal| and returns true. Otherwise
+  // returns false and |bsVal| is untouched. |bsVal| must not be NULL.
+  bool GenericName(const CFX_ByteString& bsKey, CFX_ByteString* bsVal) const;
+
  private:
   CPDF_Dictionary* GetViewerPreferences() const;