Add signal strength indicator icon to WebBluetooth chooser on non-Mac desktops

content/browser/bluetooth/bluetooth_device_chooser_controller_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 <limits>
+
+#include "base/macros.h"
+#include "content/browser/bluetooth/bluetooth_device_chooser_controller.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+class BluetoothDeviceChooserControllerTest : public testing::Test {
+ public:

[Jeffrey Yasskin, 2016/08/20 00:03:29]

You should omit all of the contents of this class.

[juncai, 2016/08/20 01:17:02]

Done.

+  BluetoothDeviceChooserControllerTest() {}
+  ~BluetoothDeviceChooserControllerTest() override = default;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BluetoothDeviceChooserControllerTest);
+};
+
+TEST_F(BluetoothDeviceChooserControllerTest, CalculateSignalStrengthLevel) {
+  int low = std::numeric_limits<int8_t>::min();
+  int high = std::numeric_limits<int8_t>::max();
+  for (int rssi = low; rssi <= high; ++rssi) {

[Jeffrey Yasskin, 2016/08/20 00:03:29]

Instead of the exhaustive test, check some concrete values, like:

EXPECT_EQ(0,
content::BluetoothDeviceChooserController::CalculateSignalStrengthLevel(-128));
EXPECT_EQ(0,
content::BluetoothDeviceChooserController::CalculateSignalStrengthLevel(-100));
EXPECT_EQ(0,
content::BluetoothDeviceChooserController::CalculateSignalStrengthLevel(-89));
EXPECT_EQ(1,
content::BluetoothDeviceChooserController::CalculateSignalStrengthLevel(-88));
EXPECT_EQ(3,
content::BluetoothDeviceChooserController::CalculateSignalStrengthLevel(-56));
EXPECT_EQ(4,
content::BluetoothDeviceChooserController::CalculateSignalStrengthLevel(-55));
EXPECT_EQ(4,
content::BluetoothDeviceChooserController::CalculateSignalStrengthLevel(127));

[juncai, 2016/08/20 01:17:02]

Done.

+    int level =
+        content::BluetoothDeviceChooserController::CalculateSignalStrengthLevel(
+            static_cast<int8_t>(rssi));
+    EXPECT_LE(0, level);
+    EXPECT_GE(4, level);
+  }
+}