Add private PPAPI interfaces for PDFium accessibility.

pdf/pdf_engine.h

Index: pdf/pdf_engine.h
diff --git a/pdf/pdf_engine.h b/pdf/pdf_engine.h
index c5d33c8706679fa3adcad34f29272e8436bb78d8..cbda1104713060ee692a5967cd9b6c2c95fc4ecd 100644
--- a/pdf/pdf_engine.h
+++ b/pdf/pdf_engine.h
@@ -183,6 +183,10 @@ class PDFEngine {
 
     // Sets selection status.
     virtual void IsSelectingChanged(bool is_selecting) {}
+
+    virtual int GetToolbarHeight() {
+      return 0;
+    }
   };
 
   // Factory method to create an instance of the PDF Engine.
@@ -233,7 +237,6 @@ class PDFEngine {
   virtual int GetMostVisiblePage() = 0;
   // Gets the rectangle of the page including shadow.
   virtual pp::Rect GetPageRect(int index) = 0;
-  // Gets the rectangle of the page excluding any additional areas.
   virtual pp::Rect GetPageContentsRect(int index) = 0;
   // Returns a page's rect in screen coordinates, as well as its surrounding
   // border areas and bottom separator.
@@ -247,6 +250,9 @@ class PDFEngine {
   virtual void OnCallback(int id) = 0;
   // Gets the JSON representation of the PDF file
   virtual std::string GetPageAsJSON(int index) = 0;
+  // Enable accessibility support and start sending the accessible text and
+  // other metadata to the client.
+  virtual void EnableAccessibility() = 0;
   // Gets the PDF document's print scaling preference. True if the document can
   // be scaled to fit.
   virtual bool GetPrintScaling() = 0;