Use Android callback API to obtain cellular signal strength

net/android/cellular_signal_strength_unittest.cc

 // 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 <stdint.h>
 
+#include "base/optional.h"
 #include "net/base/network_change_notifier.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace net {
 
 namespace {
 
-TEST(CellularSignalStrengthAndroidTest, SignalStrengthTest) {
-  int signal_strength_dbm = INT32_MIN;
-  bool signal_strength_available =
-      android::cellular_signal_strength::GetSignalStrengthDbm(
-          &signal_strength_dbm);
+TEST(CellularSignalStrengthAndroidTest, SignalStrengthLevelTest) {
+  android::CellularSignalStrength cellular_signal_strength;
+
+  base::Optional<int32_t> signal_strength =
+      cellular_signal_strength.GetSignalStrengthLevel();
 
   // Signal strength is unavailable if the device does not have an active
   // cellular connection.
   if (!NetworkChangeNotifier::IsConnectionCellular(
           NetworkChangeNotifier::GetConnectionType())) {
+    ASSERT_FALSE(signal_strength);
     return;
   }
 
-  EXPECT_TRUE(signal_strength_available);
-  // Signal strength (in dbM) should typically be between -130 and 0.
-  EXPECT_LE(-130, signal_strength_dbm);
-  EXPECT_GE(0, signal_strength_dbm);
-}
-
-TEST(CellularSignalStrengthAndroidTest, SignalStrengthLevelTest) {
-  int signal_strength_level = INT32_MIN;
-  bool signal_strength_level_available =
-      android::cellular_signal_strength::GetSignalStrengthLevel(
-          &signal_strength_level);
-
-  // Signal strength is unavailable if the device does not have an active
-  // cellular connection.
-  if (!NetworkChangeNotifier::IsConnectionCellular(
-          NetworkChangeNotifier::GetConnectionType())) {
-    return;
-  }
-
-  EXPECT_TRUE(signal_strength_level_available);
-  EXPECT_LE(0, signal_strength_level);
-  EXPECT_GE(4, signal_strength_level);
+  ASSERT_TRUE(signal_strength);
+  EXPECT_LE(0, signal_strength.value());
+  EXPECT_GE(4, signal_strength.value());
 }
 
 }  // namespace
 
 }  // namespace net