Cover fpdftext.h API with embeddertests.

fpdfsdk/src/fpdftext.cpp

 // 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
 
 #include "../include/fsdk_define.h"
 #include "../include/fpdftext.h"
 #include "../include/fpdfxfa/fpdfxfa_doc.h"
 #include "../include/fpdfxfa/fpdfxfa_page.h"
@@ skipping 223 matching lines @@
         pageLink->GetRects(link_index,rectArray);
         return rectArray.GetSize();
 }
 DLLEXPORT void STDCALL FPDFLink_GetRect(FPDF_PAGELINK link_page,int link_index,  int rect_index, double* left,
                                                                                 double*  top,double*  right, double*  bottom)
 {
         if (!link_page) return;
         IPDF_LinkExtract* pageLink=(IPDF_LinkExtract*)link_page;
         CFX_RectArray rectArray;
         pageLink->GetRects(link_index,rectArray);
-        CFX_FloatRect rect;
-        rect=rectArray.GetAt(rect_index);
-        *left=rect.left;
-        *right=rect.right;
-        *top=rect.top;
-        *bottom=rect.bottom;
+        if (rect_index >= 0 && rect_index < rectArray.GetSize()) {
+                CFX_FloatRect rect=rectArray.GetAt(rect_index);
+                *left=rect.left;
+                *right=rect.right;
+                *top=rect.top;
+                *bottom=rect.bottom;
+        }
 }
 DLLEXPORT void  STDCALL FPDFLink_CloseWebLinks(FPDF_PAGELINK link_page)
 {
         if (!link_page) return;
         IPDF_LinkExtract* pageLink=(IPDF_LinkExtract*)link_page;
         delete pageLink;
         pageLink =NULL;
 }