XFA: Fix a crashier in SetFocus()

public/fpdf_formfill.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef PUBLIC_FPDF_FORMFILL_H_
 #define PUBLIC_FPDF_FORMFILL_H_
 
 #include "fpdfview.h"
@@ skipping 360 matching lines @@
  */
 /*@{*/
 #define FXFA_SAVEAS_XML 1
 #define FXFA_SAVEAS_XDP 2
 /*@}*/
 #endif  // PDF_ENABLE_XFA
 
 typedef struct _FPDF_FORMFILLINFO {
   /**
    * Version number of the interface. Currently must be 1 (when PDFium is built
    *  without the XFA module) or must be 2 (when built with the XFA module).

[Tom Sepez, 2016/01/28 17:30:25]

Do we need to change the version number here to account for the API change?

[jun_fang, 2016/01/29 00:19:18]

Yes. I forgot to check the description. I will change the API version to 2 in
the next patch.

[jun_fang, 2016/01/29 12:58:44]

The comments here are used to remind applications to set a correct version like:

#ifdef PDF_ENABLE_XFA
  formfillinfo->version = 2;
#else   // PDF_ENABLE_XFA
  formfillinfo->version = 1;
#endif  // PDF_ENABLE_XFA

I update interface version to 2 but it doesn't change any behaviors.  

    **/
   int version;
 
   /* Version 1. */
   /**
    *Method: Release
    *         Give implementation a chance to release any data after the
    *         interface is no longer used
    *Interface Version:
    *         1
@@ skipping 612 matching lines @@
   * Parameters:
   *       pThis           -   Pointer to the interface structure itself.
   *       wsURL           -   The string value of the server URL, in UTF-16LE
   *format.
   *       wsData          -   The put data, in UTF-16LE format.
   *       wsEncode        -   The encode type, in UTR-16LE format.
   * Return value:
   *       TRUE indicates success, otherwise FALSE.
   **/
   FPDF_BOOL   (*FFI_PutRequestURL)(struct _FPDF_FORMFILLINFO* pThis, FPDF_WIDESTRING wsURL, FPDF_WIDESTRING wsData, FPDF_WIDESTRING wsEncode);
+
+  /**
+  * Method: FFI_PageEvent
+  *           This method will notify applications when a page is deleted or
+  *removed.
+  * Interface Version:
+  *           1
+  * Implementation Required:
+  *           yes
+  * Parameters:
+  *       pThis           -   Pointer to the interface structure itself.
+  *       iPageIndex      -   The index of which page is modified.
+  *       iEventType      -   Type of events. It can be one of
+  *the following marcos:
+  *                           1. FXFA_PAGEVIEWEVENT_POSTADDED
+  *                           2. FXFA_PAGEVIEWEVENT_POSTREMOVED
+  * Return value:
+  *       None.
+  **/
+  void (*FFI_PageEvent)(struct _FPDF_FORMFILLINFO* pThis,
+                        int iPageIndex,
+                        int iEventType);
+
 #endif  // PDF_ENABLE_XFA
 
 } FPDF_FORMFILLINFO;
 
 /**
  * Function: FPDFDOC_InitFormFillEnvironment
  *          Init form fill environment.
  * Comments:
  *          This function should be called before any form fill operation.
  * Parameters:
@@ skipping 662 matching lines @@
 FPDF_StringHandleAddString(FPDF_STRINGHANDLE stringHandle,
                            FPDF_BYTESTRING bsText,
                            FPDF_DWORD size);
 #endif  // PDF_ENABLE_XFA
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif  // PUBLIC_FPDF_FORMFILL_H_