Create a string for private DNS "On"

The last private DNS settings screen landed in P after string
freeze, which led us to reuse R.string.switch_on_text for the
"on" text when private DNS is active. That string comes from
notifications. Private DNS should have its own string for this
instead.

Bug: 79122154
Test: 1. Build pass
      2. make -j44 RunSettingsRoboTests \
      ROBOTEST_FILTER=PrivateDnsPreferenceControllerTest

Change-Id: Ie013a858c8bc41e00a1b940d02efa2b605991685
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 578c643..0e3fbd8 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -2362,6 +2362,8 @@
     <string name="emergency_address_summary">Used as your location when you make an emergency call over Wi\u2011Fi</string>
     <!-- Message of private dns that provides a help link. [CHAR LIMIT=NONE] -->
     <string name="private_dns_help_message"><annotation id="url">Learn more</annotation> about Private DNS features</string>
+    <!-- Message to display when private dns is on. [CHAR LIMIT=10] -->
+    <string name="private_dns_mode_on">On</string>
 
     <!-- Message to display when setting wifi calling are not editable [CHAR LIMIT=NONE] -->
     <string name="wifi_calling_pref_managed_by_carrier">Setting managed by carrier</string>
diff --git a/src/com/android/settings/network/PrivateDnsPreferenceController.java b/src/com/android/settings/network/PrivateDnsPreferenceController.java
index 13e5bf3..67f300c 100644
--- a/src/com/android/settings/network/PrivateDnsPreferenceController.java
+++ b/src/com/android/settings/network/PrivateDnsPreferenceController.java
@@ -119,11 +119,7 @@
             case PRIVATE_DNS_MODE_OFF:
                 return res.getString(R.string.private_dns_mode_off);
             case PRIVATE_DNS_MODE_OPPORTUNISTIC:
-                // TODO (b/79122154) : create a string specifically for this, instead of
-                // hijacking a string from notifications. This is necessary at this time
-                // because string freeze is in the past and this string has the right
-                // content at this moment.
-                return dnsesResolved ? res.getString(R.string.switch_on_text)
+                return dnsesResolved ? res.getString(R.string.private_dns_mode_on)
                         : res.getString(R.string.private_dns_mode_opportunistic);
             case PRIVATE_DNS_MODE_PROVIDER_HOSTNAME:
                 return dnsesResolved
diff --git a/tests/robotests/src/com/android/settings/network/PrivateDnsPreferenceControllerTest.java b/tests/robotests/src/com/android/settings/network/PrivateDnsPreferenceControllerTest.java
index eff20d3..39df717 100644
--- a/tests/robotests/src/com/android/settings/network/PrivateDnsPreferenceControllerTest.java
+++ b/tests/robotests/src/com/android/settings/network/PrivateDnsPreferenceControllerTest.java
@@ -186,7 +186,7 @@
         when(lp.getValidatedPrivateDnsServers()).thenReturn(NON_EMPTY_ADDRESS_LIST);
         updateLinkProperties(lp);
         mController.updateState(mPreference);
-        verify(mPreference).setSummary(getResourceString(R.string.switch_on_text));
+        verify(mPreference).setSummary(getResourceString(R.string.private_dns_mode_on));
 
         reset(mPreference);
         lp = mock(LinkProperties.class);