Remove the expat and jsoncpp to reduce the binary size.

webrtc/p2p/BUILD.gn

 # Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("../webrtc.gni")
 
@@ skipping 70 matching lines @@
     "client/socketmonitor.cc",
     "client/socketmonitor.h",
   ]
 
   defines = []
 
   deps = [
     "../base:rtc_base",
   ]
 
-  if (rtc_build_expat) {
-    deps += [ "//third_party/expat" ]
-    public_deps = [
-      "//third_party/expat",
-    ]
-  }
-
   public_configs = [ ":rtc_p2p_inherited_config" ]
 
   if (build_with_chromium) {
     if (is_nacl) {
       deps += [ "//native_client_sdk/src/libraries/nacl_io" ]
     }
   } else {
     sources += [
       "base/relayserver.cc",
       "base/relayserver.h",
@@ skipping 136 matching lines @@
       "//testing/gmock",
       "//testing/gtest",
     ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
     defines = [ "GTEST_RELATIVE_PATH" ]
   }
 }