Fix PP_FileOpenFlags_Dev handling:

base/platform_file_posix.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 "base/platform_file.h"
 
 #include <fcntl.h>
 #include <errno.h>
 #include <sys/stat.h>
 
@@ skipping 26 matching lines @@
     open_flags = O_CREAT | O_EXCL;
 
   if (created)
     *created = false;
 
   if (flags & PLATFORM_FILE_CREATE_ALWAYS) {
     DCHECK(!open_flags);
     open_flags = O_CREAT | O_TRUNC;
   }
 
+  if (flags & PLATFORM_FILE_OPEN_TRUNCATED) {
+    DCHECK(!open_flags);
+    DCHECK(flags & PLATFORM_FILE_WRITE);
+    open_flags = O_TRUNC;
+  }
+
   if (!open_flags && !(flags & PLATFORM_FILE_OPEN) &&
       !(flags & PLATFORM_FILE_OPEN_ALWAYS)) {
     NOTREACHED();
     errno = EOPNOTSUPP;
     *error_code = error_code ? PLATFORM_FILE_ERROR_FAILED : PLATFORM_FILE_OK;
     return kInvalidPlatformFileValue;
   }
 
   if (flags & PLATFORM_FILE_WRITE && flags & PLATFORM_FILE_READ) {
     open_flags |= O_RDWR;
   } else if (flags & PLATFORM_FILE_WRITE) {
     open_flags |= O_WRONLY;
   } else if (!(flags & PLATFORM_FILE_READ) &&
              !(flags & PLATFORM_FILE_WRITE_ATTRIBUTES) &&
              !(flags & PLATFORM_FILE_OPEN_ALWAYS)) {
     NOTREACHED();
   }
 
-  if (flags & PLATFORM_FILE_TRUNCATE) {
-    DCHECK(flags & PLATFORM_FILE_WRITE);
-    open_flags |= O_TRUNC;
-  }
-
   COMPILE_ASSERT(O_RDONLY == 0, O_RDONLY_must_equal_zero);
 
   int descriptor =
       HANDLE_EINTR(open(name.value().c_str(), open_flags, S_IRUSR | S_IWUSR));
 
   if (flags & PLATFORM_FILE_OPEN_ALWAYS) {
     if (descriptor <= 0) {
       open_flags |= O_CREAT;
       if (flags & PLATFORM_FILE_EXCLUSIVE_READ ||
           flags & PLATFORM_FILE_EXCLUSIVE_WRITE) {
@@ skipping 104 matching lines @@
   info->is_directory = S_ISDIR(file_info.st_mode);
   info->is_symbolic_link = S_ISLNK(file_info.st_mode);
   info->size = file_info.st_size;
   info->last_modified = base::Time::FromTimeT(file_info.st_mtime);
   info->last_accessed = base::Time::FromTimeT(file_info.st_atime);
   info->creation_time = base::Time::FromTimeT(file_info.st_ctime);
   return true;
 }
 
 }  // namespace base