GN: Don't compile battor_agent, imagediff, bitmaptools on Android

device/serial/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.
 
 import("//build/config/features.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 
+# Library works only on desktop platforms.
+assert(is_win || is_linux || is_mac)
+
 # GYP version: device/serial/serial.gyp:device_serial
 static_library("serial") {
   output_name = "device_serial"
 
   sources = [
     "buffer.cc",
     "buffer.h",
     "data_receiver.cc",
     "data_receiver.h",
     "data_sender.cc",
@@ skipping 65 matching lines @@
     "//extensions:extensions_renderer_resources_grit",
   ]
 
   sources = [
     "data_stream.mojom",
     "data_stream_serialization.mojom",
     "serial.mojom",
     "serial_serialization.mojom",
   ]
 }