Another round of PDF plugin cleanups.

pdf/pdfium/pdfium_page.h

Index: pdf/pdfium/pdfium_page.h
diff --git a/pdf/pdfium/pdfium_page.h b/pdf/pdfium/pdfium_page.h
index eee57e0f76c8173ce5e342ab0b50a4ab6262946c..da30504b1536223943e296fd5e1c476e468a882c 100644
--- a/pdf/pdfium/pdfium_page.h
+++ b/pdf/pdfium/pdfium_page.h
@@ -30,6 +30,7 @@ class PDFiumPage {
              const pp::Rect& r,
              bool available);
   ~PDFiumPage();
+
   // Unloads the PDFium data for this page from memory.
   void Unload();
   // Gets the FPDF_PAGE for this page, loading and parsing it if necessary.
@@ -79,7 +80,7 @@ class PDFiumPage {
                         double top,
                         double right,
                         double bottom,
-                        int rotation);
+                        int rotation) const;
 
   int index() const { return index_; }
   pp::Rect rect() const { return rect_; }
@@ -102,9 +103,9 @@ class PDFiumPage {
   void CalculateLinks();
   // Returns link type and target associated with a link. Returns
   // NONSELECTABLE_AREA if link detection failed.
-  Area GetLinkTarget(FPDF_LINK link, LinkTarget* target);
+  Area GetLinkTarget(FPDF_LINK link, LinkTarget* target) const;
   // Returns target associated with a destination.
-  Area GetDestinationTarget(FPDF_DEST destination, LinkTarget* target);
+  Area GetDestinationTarget(FPDF_DEST destination, LinkTarget* target) const;
   // Returns the text in the supplied box as a Value Node
   base::Value* GetTextBoxAsValue(double page_height, double left, double top,
                                  double right, double bottom, int rotation);