PDF: Yet another stab at getting WriteInto() buffer sizes correct.

pdf/pdfium/pdfium_engine.cc

Index: pdf/pdfium/pdfium_engine.cc
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index 228a8899cc4f5436c1ca4b7f7015ce40e68d05da..6d828a44f6fa4590f499b97276a21061f7d55cda 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -2076,10 +2076,12 @@ void PDFiumEngine::SearchUsingICU(const base::string16& term,
                                  character_to_start_searching_from,
                                  text_length,
                                  data);
-  if (written < 1)
-    page_text.resize(0);
-  else
+  if (written > 0) {
+    DCHECK_EQ(L'\0', page_text[written - 1]);
     page_text.resize(written - 1);
+  } else {
+    page_text.clear();
+  }
 
   std::vector<PDFEngine::Client::SearchStringResult> results;
   client_->SearchString(