Remove net::Filter direct dependency on IsSupportedMimeType

net/filter/filter.cc

Index: net/filter/filter.cc
diff --git a/net/filter/filter.cc b/net/filter/filter.cc
index b3f98cbcc6d501d9f46ba710bcf33828a770febd..edadc0f798d0def01d7355765c5817255eda314f 100644
--- a/net/filter/filter.cc
+++ b/net/filter/filter.cc
@@ -27,7 +27,6 @@
 #include "base/strings/string_util.h"
 #include "net/base/filename_util_unsafe.h"
 #include "net/base/io_buffer.h"
-#include "net/base/mime_util.h"
 #include "net/base/sdch_net_log_params.h"
 #include "net/filter/gzip_filter.h"
 #include "net/filter/sdch_filter.h"
@@ -249,9 +248,12 @@ void Filter::FixupEncodingTypes(
       // However, if it's not a supported mime type, then we will attempt to
       // download it, and in that case, don't decompress .gz/.tgz files.
       if ((EndsWith(extension, FILE_PATH_LITERAL(".gz"), false) ||
-           LowerCaseEqualsASCII(extension, ".tgz")) &&
-          !IsSupportedMimeType(mime_type))
-        encoding_types->clear();
+           LowerCaseEqualsASCII(extension, ".tgz"))) {
+        NetworkDelegate* net_delegate =
+            filter_context.GetURLRequestContext()->network_delegate();
+        if (net_delegate && !net_delegate->IsSupportedMimeType(mime_type))
+          encoding_types->clear();
+      }
     }
   }