Remove an old TODO in net/base.

net/base/platform_mime_util_linux.cc

Index: net/base/platform_mime_util_linux.cc
diff --git a/net/base/platform_mime_util_linux.cc b/net/base/platform_mime_util_linux.cc
index ff7f79b1549fe81313df94c66e572f0a5b739926..1480cab8d7a7f138b397064b1da8a363cbe72205 100644
--- a/net/base/platform_mime_util_linux.cc
+++ b/net/base/platform_mime_util_linux.cc
@@ -25,13 +25,6 @@ bool PlatformMimeUtil::GetPlatformMimeTypeFromExtension(
 #else
 bool PlatformMimeUtil::GetPlatformMimeTypeFromExtension(
     const base::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;
-
   base::FilePath dummy_path("foo." + ext);
   std::string out = base::nix::GetFileMimeType(dummy_path);