Roll font-compression-reference

To fix build error on Windows.

https://code.google.com/p/font-compression-reference/source/detail?r=6cef49677dc4c650ef6e3f56041e0a41803afa8c

Review URL: https://codereview.chromium.org/315393005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275456 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -177,7 +177,7 @@ deps = {
 
   "src/third_party/brotli/src":
     Var("chromium_git") +
-    "/external/font-compression-reference.git@c75ed764ef2a74bf3ab645ca7a73c0c692477755",
+    "/external/font-compression-reference.git@6cef49677dc4c650ef6e3f56041e0a41803afa8c",
 
   "src/tools/page_cycler/acid3":
     "/trunk/deps/page_cycler/acid3@171600",