Log some actions for changing wifi hotspot config

Log following actions:
- wifi hotspot name changed
- wifi hotspot password changed

Added tests for logging actions in each controller's test.

Bug: 151113705
Test: WifiTetherSSIDPrefereceControllerTest;
WifiTetherPasswordPreferenceControllerTest;
CodeInspectionTest

Change-Id: I84b1cd8449e575a6ee1ad8868e7791dc601e726f

src/com/android/settings/wifi/tether/WifiTetherSSIDPreferenceController.java

@@ -22,6 +22,7 @@ import android.app.settings.SettingsEnums;
 import android.content.Context;
 import android.content.Intent;
 import android.net.wifi.SoftApConfiguration;
+import android.text.TextUtils;
 import android.util.FeatureFlagUtils;
 import android.util.Log;
 
@@ -48,6 +49,15 @@ public class WifiTetherSSIDPreferenceController extends WifiTetherBasePreference
 
     private final MetricsFeatureProvider mMetricsFeatureProvider;
 
+    // This constructor is used for testing.
+    @VisibleForTesting
+    WifiTetherSSIDPreferenceController(Context context, OnTetherConfigUpdateListener listener,
+            MetricsFeatureProvider provider) {
+        super(context, listener);
+        mWifiDeviceNameTextValidator = new WifiDeviceNameTextValidator();
+        mMetricsFeatureProvider = provider;
+    }
+
     public WifiTetherSSIDPreferenceController(Context context,
             OnTetherConfigUpdateListener listener) {
         super(context, listener);
@@ -93,6 +103,10 @@ public class WifiTetherSSIDPreferenceController extends WifiTetherBasePreference
 
     @Override
     public boolean onPreferenceChange(Preference preference, Object newValue) {
+        if (!TextUtils.equals(mSSID, (String) newValue)) {
+            mMetricsFeatureProvider.action(mContext,
+                    SettingsEnums.ACTION_SETTINGS_CHANGE_WIFI_HOTSPOT_NAME);
+        }
         mSSID = (String) newValue;
         updateSsidDisplay((EditTextPreference) preference);
         mListener.onTetherConfigUpdated(this);