Linux: Move base/mime_util* to base/nix. It's not used on any other platform.

chrome/browser/icon_manager_linux.cc

Index: chrome/browser/icon_manager_linux.cc
===================================================================
--- chrome/browser/icon_manager_linux.cc	(revision 109608)
+++ chrome/browser/icon_manager_linux.cc	(working copy)
@@ -4,16 +4,16 @@
 
 #include "chrome/browser/icon_manager.h"
 
-#include "base/mime_util.h"
+#include "base/nix/mime_util_xdg.h"
 #include "base/threading/thread_restrictions.h"
 
 IconGroupID IconManager::GetGroupIDFromFilepath(const FilePath& filepath) {
-  // It turns out the call to mime_util::GetFileMimeType below does IO, but
+  // It turns out the call to base::nix::GetFileMimeType below does IO, but
   // callers of GetGroupIDFromFilepath assume it does not do IO (the Windows
   // and Mac implementations do not). We should fix this by either not doing IO
   // in this method, or reworking callers to avoid calling it on the UI thread.
   // See crbug.com/72740.
   base::ThreadRestrictions::ScopedAllowIO allow_io;
 
-  return mime_util::GetFileMimeType(filepath);
+  return base::nix::GetFileMimeType(filepath);
 }