Add jsoncpp in DEPS and the gyp file to build jsoncpp in chromium.

third_party/jsoncpp/jsoncpp.gyp

+# Copyright (c) 2011 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.
+
+{
+  'targets': [
+    {
+      'target_name': 'jsoncpp',
+      'type': 'static_library',
+      'defines': [
+        'JSON_USE_EXCEPTION=0',
+      ],
+      'sources': [
+        'source/include/json/assertions.h',
+        'source/include/json/autolink.h',
+        'source/include/json/config.h',
+        'source/include/json/features.h',
+        'source/include/json/forwards.h',
+        'source/include/json/json.h',
+        'source/include/json/reader.h',
+        'source/include/json/value.h',
+        'source/include/json/writer.h',
+        'source/src/lib_json/json_batchallocator.h',
+        'source/src/lib_json/json_reader.cpp',
+        'source/src/lib_json/json_tool.h',
+        'source/src/lib_json/json_value.cpp',
+        'source/src/lib_json/json_writer.cpp',
+      ],
+      'include_dirs': [
+        'source/include/',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          'source/include/',
+        ],
+      },
+    },
+  ],
+}
+
+# Local Variables:
+# tab-width:2
+# indent-tabs-mode:nil
+# End:
+# vim: set expandtab tabstop=2 shiftwidth=2: