Make string_util::WriteInto() DCHECK() that the supplied |length_with_null| > 1, meaning that the...

chrome_frame/test/win_event_receiver.cc

 // Copyright (c) 2011 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 "chrome_frame/test/win_event_receiver.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
@@ skipping 151 matching lines @@
     i = (observer == i->observer) ? observers_.erase(i) : ++i;
   }
 
   if (observers_.empty())
     win_event_receiver_.StopReceivingEvents();
 }
 
 std::string WindowWatchdog::GetWindowCaption(HWND hwnd) {
   std::string caption;
   int len = ::GetWindowTextLength(hwnd) + 1;
-  ::GetWindowTextA(hwnd, WriteInto(&caption, len), len);
-
+  if (len > 1)
+    ::GetWindowTextA(hwnd, WriteInto(&caption, len), len);
   return caption;
 }
 
 bool WindowWatchdog::MatchingWindow(const ObserverEntry& entry,
                                     const std::string& caption,
                                     const std::string& class_name) {
   bool should_match_caption = !entry.caption_pattern.empty();
   bool should_match_class = !entry.class_name_pattern.empty();
 
   if (should_match_caption &&
@@ skipping 82 matching lines @@
     HandleOnOpen(hwnd);
   } else {
     DCHECK(event == EVENT_OBJECT_DESTROY || event == EVENT_OBJECT_HIDE);
     HandleOnClose(hwnd);
   }
 }
 
 void WindowWatchdog::OnHwndProcessExited(HWND hwnd) {
   HandleOnClose(hwnd);
 }