Expose cellular signal strength on Android to native

net/android/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/android/config.gni")
 import("//build/config/android/rules.gni")
 
 android_library("net_java") {
   java_files = [
+    "java/src/org/chromium/net/AndroidCellularSignalStrength.java",
     "java/src/org/chromium/net/AndroidCertVerifyResult.java",
     "java/src/org/chromium/net/AndroidKeyStore.java",
     "java/src/org/chromium/net/AndroidNetworkLibrary.java",
     "java/src/org/chromium/net/AndroidTrafficStats.java",
     "java/src/org/chromium/net/GURLUtils.java",
     "java/src/org/chromium/net/HttpNegotiateAuthenticator.java",
     "java/src/org/chromium/net/HttpNegotiateConstants.java",
     "java/src/org/chromium/net/NetStringUtil.java",
     "java/src/org/chromium/net/NetworkChangeNotifier.java",
     "java/src/org/chromium/net/NetworkChangeNotifierAutoDetect.java",
@@ skipping 119 matching lines @@
 java_cpp_enum("net_java_test_support_enums_srcjar") {
   sources = [
     "../test/url_request/url_request_failed_job.h",
   ]
 }
 
 java_cpp_enum("net_android_java_enums_srcjar") {
   sources = [
     "../base/mime_util.h",
     "../base/network_change_notifier.h",
+    "cellular_signal_strength.cc",
     "cert_verify_result_android.h",
     "keystore.h",
     "network_change_notifier_android.cc",
     "traffic_stats.cc",
   ]
 }
 
 junit_binary("net_junit_tests") {
   java_files =
       [ "junit/src/org/chromium/net/HttpNegotiateAuthenticatorTest.java" ]
   deps = [
     ":net_java",
     "//base:base_java",
     "//base:base_java_test_support",
     "//base:base_junit_test_support",
     "//third_party/junit:hamcrest",
   ]
 }