Add browser_tests to the GN build.

sdch/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 config("sdch_config") {
   include_dirs = [ "open-vcdiff/src" ]
 }
 
 static_library("sdch") {
   sources = [
     "logging_forward.h",
     "open-vcdiff/src/addrcache.cc",
     "open-vcdiff/src/blockhash.cc",
     "open-vcdiff/src/blockhash.h",
     "open-vcdiff/src/checksum.h",
     "open-vcdiff/src/codetable.cc",
     "open-vcdiff/src/codetable.h",
     "open-vcdiff/src/compile_assert.h",
     "open-vcdiff/src/decodetable.cc",
     "open-vcdiff/src/decodetable.h",
     "open-vcdiff/src/encodetable.cc",
     "open-vcdiff/src/encodetable.h",
     "open-vcdiff/src/google/output_string.h",
     "open-vcdiff/src/google/vcdecoder.h",
+    "open-vcdiff/src/google/vcencoder.h",
     "open-vcdiff/src/headerparser.cc",
     "open-vcdiff/src/headerparser.h",
     "open-vcdiff/src/instruction_map.cc",
     "open-vcdiff/src/instruction_map.h",
+    "open-vcdiff/src/jsonwriter.h",
+    "open-vcdiff/src/jsonwriter.cc",
     "open-vcdiff/src/rolling_hash.h",
     "open-vcdiff/src/testing.h",
     "open-vcdiff/src/varint_bigendian.cc",
     "open-vcdiff/src/varint_bigendian.h",
     "open-vcdiff/src/vcdecoder.cc",
+    "open-vcdiff/src/vcencoder.cc",
     "open-vcdiff/src/vcdiff_defs.h",
     "open-vcdiff/src/vcdiffengine.cc",
     "open-vcdiff/src/vcdiffengine.h",
     "open-vcdiff/vsprojects/config.h",
     "open-vcdiff/vsprojects/stdint.h",
   ]
 
   public_configs = [ ":sdch_config" ]
 
   deps = [
@@ skipping 42 matching lines @@
       "sdch/logging_forward.h",
     ]
   } else {
     logging_file = rebase_path("logging_forward.h", root_build_dir)
     cflags = [
       "-include",
       logging_file,
     ]
   }
 }