PDF: Fix extra NUL characters from incorrect WriteInto() calls.

pdf/pdfium/pdfium_engine.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "pdf/pdfium/pdfium_engine.h"
 
 #include <math.h>
 
 #include "base/json/json_writer.h"
 #include "base/logging.h"
@@ skipping 2032 matching lines @@
   int text_length = pages_[current_page]->GetCharCount();
   if (character_to_start_searching_from) {
     text_length -= character_to_start_searching_from;
   } else if (!first_search &&
              last_character_index_to_search_ != -1 &&
              current_page == last_page_to_search_) {
     text_length = last_character_index_to_search_;
   }
   if (text_length <= 0)
     return;
+
   unsigned short* data =
       reinterpret_cast<unsigned short*>(WriteInto(&page_text, text_length + 1));
-  FPDFText_GetText(pages_[current_page]->GetTextPage(),
-                   character_to_start_searching_from,
-                   text_length,
-                   data);
+  int written = FPDFText_GetText(pages_[current_page]->GetTextPage(),
+                                 character_to_start_searching_from,
+                                 text_length,
+                                 data);
+  if (written < 1)
+    page_text.resize(0);
+  else
+    page_text.resize(written - 1);
+
   std::vector<PDFEngine::Client::SearchStringResult> results;
   client_->SearchString(
       page_text.c_str(), term.c_str(), case_sensitive, &results);
   for (size_t i = 0; i < results.size(); ++i) {
     // Need to map the indexes from the page text, which may have generated
     // characters like space etc, to character indices from the page.
     int temp_start = results[i].start_index + character_to_start_searching_from;
     int start = FPDFText_GetCharIndexFromTextIndex(
         pages_[current_page]->GetTextPage(), temp_start);
     int end = FPDFText_GetCharIndexFromTextIndex(
@@ skipping 1812 matching lines @@
     double* height) {
   FPDF_DOCUMENT doc = FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, NULL);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf