Add functions to collect bookmarks from Pdfium

pdf/pdf_engine.h

Index: pdf/pdf_engine.h
diff --git a/pdf/pdf_engine.h b/pdf/pdf_engine.h
index b81494f02fa8c287ce169871e7844422d0f0cd8a..a9f828e53c36ef158476a3460949b304fe4122c0 100644
--- a/pdf/pdf_engine.h
+++ b/pdf/pdf_engine.h
@@ -24,6 +24,7 @@
 #include "ppapi/cpp/rect.h"
 #include "ppapi/cpp/size.h"
 #include "ppapi/cpp/url_loader.h"
+#include "ppapi/cpp/var_array.h"
 
 namespace pp {
 class InputEvent;
@@ -246,6 +247,14 @@ class PDFEngine {
   // Returns number of copies to be printed.
   virtual int GetCopiesToPrint() = 0;
 
+  // Returns a VarArray of Bookmarks, each a VarDictionary containing the
+  // following key/values:
+  // - "title" - a string Var.
+  // - "page" - an int Var.
+  // - "children" - a VarArray(), with each entry containing a VarDictionary of
+  //   the same structure.
+  virtual pp::VarArray GetBookmarks() = 0;
+
   // Append blank pages to make a 1-page document to a |num_pages| document.
   // Always retain the first page data.
   virtual void AppendBlankPages(int num_pages) = 0;