Add private PPAPI interfaces for PDFium accessibility.

pdf/out_of_process_instance.h

Index: pdf/out_of_process_instance.h
diff --git a/pdf/out_of_process_instance.h b/pdf/out_of_process_instance.h
index 0842d33bde12371729a40d223757931d066b80a1..8fbce945e5b96ab721699b57c48b0e933c83b657 100644
--- a/pdf/out_of_process_instance.h
+++ b/pdf/out_of_process_instance.h
@@ -77,6 +77,7 @@ class OutOfProcessInstance : public pp::Instance,
   // pp::Private implementation.
   pp::Var GetLinkAtPosition(const pp::Point& point);
   void GetPrintPresetOptionsFromDocument(PP_PdfPrintPresetOptions_Dev* options);
+  void EnableAccessibility();
 
   void FlushCallback(int32_t result);
   void DidOpen(int32_t result);
@@ -133,6 +134,7 @@ class OutOfProcessInstance : public pp::Instance,
   bool IsPrintPreview() override;
   uint32_t GetBackgroundColor() override;
   void IsSelectingChanged(bool is_selecting) override;
+  int GetToolbarHeight() override;
 
   // PreviewModeClient::Client implementation.
   void PreviewDocumentLoadComplete() override;