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..2b0ebee7daebe38aeda07ebfeb535837d5cac898 100644
--- a/pdf/out_of_process_instance.h
+++ b/pdf/out_of_process_instance.h
@@ -77,6 +77,10 @@ class OutOfProcessInstance : public pp::Instance,
   // pp::Private implementation.
   pp::Var GetLinkAtPosition(const pp::Point& point);
   void GetPrintPresetOptionsFromDocument(PP_PdfPrintPresetOptions_Dev* options);
+  void EnableAccessibility();
+
+  // Send accessibility information about the given page index.
+  void SendNextAccessibilityPage(int32_t page_index);
 
   void FlushCallback(int32_t result);
   void DidOpen(int32_t result);
@@ -342,6 +346,9 @@ class OutOfProcessInstance : public pp::Instance,
   // toolbar.
   int top_toolbar_height_;
 
+  // Whether we should send accessibility information about the loaded PDF.
+  bool accessibility_enabled_;
+
   DISALLOW_COPY_AND_ASSIGN(OutOfProcessInstance);
 };