Fix PP_FileOpenFlags_Dev handling:

chrome/browser/extensions/extension_file_browser_private_api.cc

Index: chrome/browser/extensions/extension_file_browser_private_api.cc
diff --git a/chrome/browser/extensions/extension_file_browser_private_api.cc b/chrome/browser/extensions/extension_file_browser_private_api.cc
index 0be5fa8a941cfaa35c031add0a4c6a4df5aa9511..9d53ce370388d95c34b380e64a1ef7c0b9b475be 100644
--- a/chrome/browser/extensions/extension_file_browser_private_api.cc
+++ b/chrome/browser/extensions/extension_file_browser_private_api.cc
@@ -63,12 +63,12 @@ const int kReadWriteFilePermissions = base::PLATFORM_FILE_OPEN |
                                       base::PLATFORM_FILE_CREATE |
                                       base::PLATFORM_FILE_OPEN_ALWAYS |
                                       base::PLATFORM_FILE_CREATE_ALWAYS |
+                                      base::PLATFORM_FILE_OPEN_TRUNCATED |
                                       base::PLATFORM_FILE_READ |
                                       base::PLATFORM_FILE_WRITE |
                                       base::PLATFORM_FILE_EXCLUSIVE_READ |
                                       base::PLATFORM_FILE_EXCLUSIVE_WRITE |
                                       base::PLATFORM_FILE_ASYNC |
-                                      base::PLATFORM_FILE_TRUNCATE |
                                       base::PLATFORM_FILE_WRITE_ATTRIBUTES;
 
 typedef std::pair<int, const FileBrowserHandler* > LastUsedHandler;