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

chrome/browser/ui/bluetooth/bluetooth_chooser_controller.cc

Index: chrome/browser/ui/bluetooth/bluetooth_chooser_controller.cc
diff --git a/chrome/browser/ui/bluetooth/bluetooth_chooser_controller.cc b/chrome/browser/ui/bluetooth/bluetooth_chooser_controller.cc
index 49dccb9597a74dc264ad4d833939de0df9a7e93d..6b97053831611135ba6de1afb632d6ca138c8339 100644
--- a/chrome/browser/ui/bluetooth/bluetooth_chooser_controller.cc
+++ b/chrome/browser/ui/bluetooth/bluetooth_chooser_controller.cc
@@ -26,6 +26,27 @@ Browser* GetBrowser() {
   return browser_displayer.browser();
 }
 
+// Anything worse than or equal to this will show 0 bars.
+const int kMinRSSI = -100;
+// Anything better than or equal to this will show the maximum bars.
+const int kMaxRSSI = -55;
+// Number of RSSI levels used in the signal strength icon.
+const int kNumLevels = 5;
+
+// Received Signal Strength Indicator (RSSI) is a measurement of the power
+// present in a received radio signal.
+int CalculateSignalLevel(int8_t rssi) {
+  if (rssi <= kMinRSSI)
+    return 0;
+
+  if (rssi >= kMaxRSSI)
+    return kNumLevels - 1;
+
+  double input_range = kMaxRSSI - kMinRSSI;
+  double output_range = kNumLevels - 1;
+  return static_cast<int>((rssi - kMinRSSI) * output_range / input_range);
+}
+
 }  // namespace
 
 BluetoothChooserController::BluetoothChooserController(
@@ -40,6 +61,10 @@ BluetoothChooserController::BluetoothChooserController(
 
 BluetoothChooserController::~BluetoothChooserController() {}
 
+bool BluetoothChooserController::ShouldShowIconBeforeText() const {
+  return true;
+}
+
 base::string16 BluetoothChooserController::GetNoOptionsText() const {
   return no_devices_text_;
 }
@@ -50,12 +75,16 @@ base::string16 BluetoothChooserController::GetOkButtonLabel() const {
 }
 
 size_t BluetoothChooserController::NumOptions() const {
-  return device_ids_.size();
+  return devices_.size();
+}
+
+int BluetoothChooserController::GetSignalStrengthLevel(size_t index) const {
+  return devices_[index].signal_strength_level;
 }
 
 base::string16 BluetoothChooserController::GetOption(size_t index) const {
-  DCHECK_LT(index, device_ids_.size());
-  const std::string& device_id = device_ids_[index];
+  DCHECK_LT(index, devices_.size());
+  const std::string& device_id = devices_[index].id;
   const auto& device_name_it = device_id_to_name_map_.find(device_id);
   DCHECK(device_name_it != device_id_to_name_map_.end());
   const auto& it = device_name_map_.find(device_name_it->second);
@@ -85,9 +114,9 @@ void BluetoothChooserController::Select(size_t index) {
             BLUETOOTH_CHOOSER_EVENT_HANDLER_INVALID);
     return;
   }
-  DCHECK_LT(index, device_ids_.size());
+  DCHECK_LT(index, devices_.size());
   event_handler_.Run(content::BluetoothChooser::Event::SELECTED,
-                     device_ids_[index]);
+                     devices_[index].id);
 }
 
 void BluetoothChooserController::Cancel() {
@@ -179,10 +208,11 @@ void BluetoothChooserController::AddOrUpdateDevice(
     return;
   }
 
-  device_ids_.push_back(device_id);
+  int level = rssi ? CalculateSignalLevel(*rssi) : -1;
+  devices_.push_back({device_id, level});
   ++device_name_map_[device_name];
   if (view())
-    view()->OnOptionAdded(device_ids_.size() - 1);
+    view()->OnOptionAdded(devices_.size() - 1);
 }
 
 void BluetoothChooserController::RemoveDevice(const std::string& device_id) {
@@ -191,13 +221,13 @@ void BluetoothChooserController::RemoveDevice(const std::string& device_id) {
     return;
 
   size_t index = 0;
-  for (const auto& saved_device_id : device_ids_) {
-    if (saved_device_id != device_id) {
+  for (const auto& saved_device_info : devices_) {
+    if (saved_device_info.id != device_id) {
       ++index;
       continue;
     }
 
-    device_ids_.erase(device_ids_.begin() + index);
+    devices_.erase(devices_.begin() + index);
 
     const auto& it = device_name_map_.find(name_it->second);
     DCHECK(it != device_name_map_.end());
@@ -219,7 +249,7 @@ void BluetoothChooserController::ResetEventHandler() {
 }
 
 void BluetoothChooserController::ClearAllDevices() {
-  device_ids_.clear();
+  devices_.clear();
   device_id_to_name_map_.clear();
   device_name_map_.clear();
 }