aura: Make 'net' build with gtk disabled.

net/base/platform_mime_util_linux.cc

-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// 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 "net/base/platform_mime_util.h"
 
 #include <string>
 
+#include "base/logging.h"
 #include "build/build_config.h"
 
 #if defined(OS_ANDROID)
 #include "net/android/network_library.h"
 #else
 #include "base/mime_util.h"
 #endif
 
 namespace net {
 
 #if defined(OS_ANDROID)
-
 bool PlatformMimeUtil::GetPlatformMimeTypeFromExtension(
     const FilePath::StringType& ext, std::string* result) const {
   return android::GetMimeTypeFromExtension(ext, result);
 }
-
+#elif defined(USE_AURA)
+bool PlatformMimeUtil::GetPlatformMimeTypeFromExtension(
+    const FilePath::StringType& ext, std::string* result) const {
+  NOTIMPLEMENTED();
+  return false;
+}
 #else
-
 bool PlatformMimeUtil::GetPlatformMimeTypeFromExtension(
     const FilePath::StringType& ext, std::string* result) const {
   // TODO(thestig) This is a temporary hack until we can fix this
   // properly in test shell / webkit.
   // We have to play dumb and not return application/x-perl here
   // to make the reload-subframe-object layout test happy.
   if (ext == "pl")
     return false;
 
   FilePath dummy_path("foo." + ext);
@@ skipping 56 matching lines @@
   //
   // If we wanted to do this properly, we would read the mime.cache file which
   // has a section where they assign a glob (*.gif) to a mimetype
   // (image/gif). We look up the "heaviest" glob for a certain mime type and
   // then then try to chop off "*.".
 
   return false;
 }
 
 }  // namespace net