Mac: Some clang appeasing.

net/base/mime_sniffer.cc

 // Copyright (c) 2010 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.
 
 // Detecting mime types is a tricky business because we need to balance
 // compatibility concerns with security issues.  Here is a survey of how other
 // browsers behave and then a description of how we intend to behave.
 //
 // HTML payload, no Content-Type header:
 // * IE 7: Render as HTML
@@ skipping 210 matching lines @@
   const size_t len = magic_entry->magic_len;
 
   // Keep kBytesRequiredForMagic honest.
   DCHECK_LE(len, kBytesRequiredForMagic);
 
   // To compare with magic strings, we need to compute strlen(content), but
   // content might not actually have a null terminator.  In that case, we
   // pretend the length is content_size.
   const char* end =
       static_cast<const char*>(memchr(content, '\0', size));
-  const size_t content_strlen = (end != NULL) ? (end - content) : size;
+  const size_t content_strlen =
+      (end != NULL) ? static_cast<size_t>(end - content) : size;
 
   bool match = false;
   if (magic_entry->is_string) {
     if (content_strlen >= len) {
       // String comparisons are case-insensitive
       match = (base::strncasecmp(magic_entry->magic, content, len) == 0);
     }
   } else {
     if (size >= len)
       match = (memcmp(magic_entry->magic, content, len) == 0);
@@ skipping 412 matching lines @@
   // Now we look in our large table of magic numbers to see if we can find
   // anything that matches the content.
   if (SniffForMagicNumbers(content, content_size,
                            &have_enough_content, result))
     return true;  // We've matched a magic number.  No more content needed.
 
   return have_enough_content;
 }
 
 }  // namespace net