Remove unused PDFEngine ScrollPosition getter/setter.

pdf/pdfium/pdfium_engine.h

Index: pdf/pdfium/pdfium_engine.h
diff --git a/pdf/pdfium/pdfium_engine.h b/pdf/pdfium/pdfium_engine.h
index e6392b4a482d433e56dbab35b45a9b770f5c6f8e..f8bbbd1ebf632dbd8edce2d42926a43408ebea46 100644
--- a/pdf/pdfium/pdfium_engine.h
+++ b/pdf/pdfium/pdfium_engine.h
@@ -104,8 +104,6 @@ class PDFiumEngine : public PDFEngine,
   bool GetPageSizeAndUniformity(pp::Size* size) override;
   void AppendBlankPages(int num_pages) override;
   void AppendPage(PDFEngine* engine, int index) override;
-  pp::Point GetScrollPosition() override;
-  void SetScrollPosition(const pp::Point& position) override;
   bool IsProgressiveLoad() override;
   std::string GetMetadata(const std::string& key) override;