Add UMA for WebBluetooth RSSI signal strength level

content/browser/bluetooth/bluetooth_device_chooser_controller.cc

Index: content/browser/bluetooth/bluetooth_device_chooser_controller.cc
diff --git a/content/browser/bluetooth/bluetooth_device_chooser_controller.cc b/content/browser/bluetooth/bluetooth_device_chooser_controller.cc
index 95315cdf512aedaaef0d8f4415258688de7d0eda..4bf4b2e761b64a268464d46d833d922ed80dc200 100644
--- a/content/browser/bluetooth/bluetooth_device_chooser_controller.cc
+++ b/content/browser/bluetooth/bluetooth_device_chooser_controller.cc
@@ -35,6 +35,13 @@ const int kMaxRSSI = -55;
 // Number of RSSI levels used in the signal strength image.
 const int kNumSignalStrengthLevels = 5;
 
+const content::UMARSSISignalStrengthLevel kRSSISignalStrengthEnumTable[] = {
+    content::UMARSSISignalStrengthLevel::LEVEL_0,
+    content::UMARSSISignalStrengthLevel::LEVEL_1,
+    content::UMARSSISignalStrengthLevel::LEVEL_2,
+    content::UMARSSISignalStrengthLevel::LEVEL_3,
+    content::UMARSSISignalStrengthLevel::LEVEL_4};
+
 }  // namespace
 
 namespace content {
@@ -384,15 +391,25 @@ void BluetoothDeviceChooserController::AdapterPoweredChanged(bool powered) {
 
 int BluetoothDeviceChooserController::CalculateSignalStrengthLevel(
     int8_t rssi) {
-  if (rssi <= kMinRSSI)
+  RecordRSSISignalStrength(rssi);
+
+  if (rssi <= kMinRSSI) {
+    RecordRSSISignalStrengthLevel(
+        UMARSSISignalStrengthLevel::LESS_THAN_OR_EQUAL_TO_MIN_RSSI);
     return 0;
+  }
 
-  if (rssi >= kMaxRSSI)
+  if (rssi >= kMaxRSSI) {
+    RecordRSSISignalStrengthLevel(
+        UMARSSISignalStrengthLevel::GREATER_THAN_OR_EQUAL_TO_MAX_RSSI);
     return kNumSignalStrengthLevels - 1;
+  }
 
   double input_range = kMaxRSSI - kMinRSSI;
   double output_range = kNumSignalStrengthLevels - 1;
-  return static_cast<int>((rssi - kMinRSSI) * output_range / input_range);
+  int level = static_cast<int>((rssi - kMinRSSI) * output_range / input_range);
+  RecordRSSISignalStrengthLevel(kRSSISignalStrengthEnumTable[level]);

[scheib, 2016/10/31 22:22:32]

DCHECK(kNumSignalStrengthLevels == arraysize(kRSSISignalStrengthEnumTable));

[juncai, 2016/10/31 23:29:50]

Done.

+  return level;
 }
 
 void BluetoothDeviceChooserController::SetTestScanDurationForTesting() {