Expose cellular signal strength on Android to native

net/android/cellular_signal_strength.cc

Index: net/android/cellular_signal_strength.cc
diff --git a/net/android/cellular_signal_strength.cc b/net/android/cellular_signal_strength.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b234506205c6ce5f42a9beae6eefa9cc1660280d
--- /dev/null
+++ b/net/android/cellular_signal_strength.cc
@@ -0,0 +1,48 @@
+// Copyright 2016 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.
+
+#include "net/android/cellular_signal_strength.h"
+
+#include "base/android/context_utils.h"
+#include "jni/AndroidCellularSignalStrength_jni.h"
+
+namespace net {
+
+namespace android {
+
+namespace cellular_signal_strength {
+
+const int64_t kInvalid = INT64_MIN;
+
+bool GetRssiDbm(int64_t* rssi) {
+  int64_t rssi_tmp = Java_AndroidCellularSignalStrength_getRssiDbm(
+      base::android::AttachCurrentThread(),
+      base::android::GetApplicationContext(), kInvalid);
+  if (rssi_tmp == kInvalid)
+    return false;
+
+  *rssi = rssi_tmp;
+  return true;
+}
+
+bool GetSignalLevel(int64_t* signal_level) {
+  int64_t signal_level_tmp = Java_AndroidCellularSignalStrength_getSignalLevel(
+      base::android::AttachCurrentThread(),
+      base::android::GetApplicationContext(), kInvalid);
+  if (signal_level_tmp == kInvalid)
+    return false;
+
+  *signal_level = signal_level_tmp;
+  return true;
+}
+
+bool Register(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace cellular_signal_strength
+
+}  // namespace android
+
+}  // namespace net