Add brotli content-encoding filter.

net/net.gyp

Index: net/net.gyp
diff --git a/net/net.gyp b/net/net.gyp
index 1749a46246ba395b797266bc7b442453c56bfc56..3b773d503d6d824e6bb1caec50d260a3cefdf05c 100644
--- a/net/net.gyp
+++ b/net/net.gyp
@@ -132,6 +132,7 @@
         '../crypto/crypto.gyp:crypto_test_support',
         '../testing/gmock.gyp:gmock',
         '../testing/gtest.gyp:gtest',
+        '../third_party/brotli/brotli.gyp:brotli',
         '../third_party/zlib/zlib.gyp:zlib',
         '../url/url.gyp:url_lib',
         'balsa',
@@ -272,6 +273,15 @@
               'http_server',
             ],
         }],
+        [ 'disable_brotli_support==1', {
+            'sources!': [
+              'filter/brotli_filter_unittest.cc',
+            ],
+            'dependencies!': [
+              '../third_party/brotli/brotli.gyp:brotli',
+            ],
+          },
+        ],
         ['disable_file_support==1', {
           'sources!': [
             'base/directory_lister_unittest.cc',
@@ -381,6 +391,7 @@
               'disk_cache/backend_unittest.cc',
               'disk_cache/blockfile/block_files_unittest.cc',
               # Need to read input data files.
+              'filter/brotli_filter_unittest.cc',
               'filter/gzip_filter_unittest.cc',
               # Need TestServer.
               "cert_net/cert_net_fetcher_impl_unittest.cc",