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

pdf/pdfium/pdfium_range.cc

Index: pdf/pdfium/pdfium_range.cc
diff --git a/pdf/pdfium/pdfium_range.cc b/pdf/pdfium/pdfium_range.cc
index 226d51284136ebb35fe0cd3b93c015da702224b9..c941d8e905fd6db99fadda0e04bbc57fb072a799 100644
--- a/pdf/pdfium/pdfium_range.cc
+++ b/pdf/pdfium/pdfium_range.cc
@@ -71,10 +71,12 @@ base::string16 PDFiumRange::GetText() {
     // |written| includes the trailing terminator, so get rid of the trailing
     // NUL character by calling resize().
     int written = FPDFText_GetText(page_->GetTextPage(), index, count, data);
-    if (written < 1)
-      rv.resize(0);
-    else
+    if (written > 0) {
+      DCHECK_EQ(L'\0', rv[written - 1]);
       rv.resize(written - 1);
+    } else {
+      rv.clear();
+    }
   }
 
   return rv;