Roll Brotli 931479d735e1 -> dfc5a9f2151a

This brings in Brotli format change and bug fixes.

dfc5a9f2151a Fix -Wconversion compiler warnings in the brotli decoder.
4c8c7fd31c6a Brotli format change: small improvement to the encoding of Huffman codes
efbc1a896593 Small update to brotli specification.
40955ce409e5 Bug fixes for the brotli encoder and decoder.
b89f3be40b69 Brotli format change: improved encoding of Huffman codes
30625ba238fc Use C-style comments in the brotli decoder.

BUG=307828,329547,329258,331253

Review URL: https://codereview.chromium.org/109283009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243801 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -166,7 +166,7 @@ deps = {
 
   "src/third_party/brotli/src":
     Var("chromium_git") +
-    "/external/font-compression-reference.git@931479d735e1121548c3b07aec866fd772cc4932",
+    "/external/font-compression-reference.git@dfc5a9f2151a7c88914c236c7db8fa119fee249c",
 
   "src/tools/page_cycler/acid3":
     "/trunk/deps/page_cycler/acid3@171600",