Add private PPAPI interfaces for PDFium accessibility.

ppapi/cpp/private/pdf.h

Index: ppapi/cpp/private/pdf.h
diff --git a/ppapi/cpp/private/pdf.h b/ppapi/cpp/private/pdf.h
index 755c9c32faab6cad6065ecf8778bec4e6858042b..3cd7aeb3911ed8b923b6324500405f3591987e1f 100644
--- a/ppapi/cpp/private/pdf.h
+++ b/ppapi/cpp/private/pdf.h
@@ -58,6 +58,17 @@ class PDF {
                                         int* natives_size_out,
                                         const char** snapshot_data_out,
                                         int* snapshot_size_out);
+  static void SetAccessibilityViewportInfo(
+      const InstanceHandle& instance,
+      PP_PrivateAccessibilityViewportInfo* viewport_info);
+  static void SetAccessibilityDocInfo(
+      const InstanceHandle& instance,
+      PP_PrivateAccessibilityDocInfo* doc_info);
+  static void SetAccessibilityPageInfo(
+      const InstanceHandle& instance,
+      PP_PrivateAccessibilityPageInfo* page_info,
+      PP_PrivateAccessibilityTextRunInfo text_runs[],
+      PP_PrivateAccessibilityCharInfo chars[]);
 };
 
 }  // namespace pp