[SDK-344] Pass in first-run information to Nimbus for targeting

app/src/main/java/org/mozilla/fenix/experiments/NimbusSetup.kt

@@ -63,7 +63,10 @@ fun createNimbus(context: Context, url: String?): NimbusApi {
             // Note: Using BuildConfig.BUILD_TYPE is important here so that it matches the value
             // passed into Glean. `Config.channel.toString()` turned out to be non-deterministic
             // and would mostly produce the value `Beta` and rarely would produce `beta`.
-            channel = BuildConfig.BUILD_TYPE
+            channel = BuildConfig.BUILD_TYPE,
+            customTargetingAttributes = mapOf(
+                "isFirstRun" to context.settings().isFirstRun.toString()
+            )
         )
         Nimbus(context, appInfo, serverSettings, errorReporter).apply {
             // This performs the minimal amount of work required to load branch and enrolment data

app/src/main/java/org/mozilla/fenix/utils/Settings.kt

@@ -352,6 +352,25 @@ class Settings(private val appContext: Context) : PreferencesHolder {
         default = false
     )
 
+    val isFirstRun: Boolean
+        get() {
+            val isFirstRun = preferences.getBoolean(
+                appContext.getPreferenceKey(R.string.pref_key_is_first_run),
+                true
+            )
+
+            if (isFirstRun) {
+                preferences.edit()
+                    .putBoolean(
+                        appContext.getPreferenceKey(R.string.pref_key_is_first_run),
+                        false
+                    )
+                    .apply()
+            }
+
+            return isFirstRun
+        }
+
     /**
      * Indicates the last time when the user was interacting with the [BrowserFragment],
      * This is useful to determine if the user has to start on the [HomeFragment]

app/src/main/res/values/preference_keys.xml

@@ -69,6 +69,7 @@
     <string name="pref_key_last_browse_activity_time" translatable="false">pref_key_last_browse_activity_time</string>
     <string name="pref_key_last_cfr_shown_time" translatable="false">pref_key_last_cfr_shown_time</string>
     <string name="pref_key_should_show_default_browser_notification" translatable="false">pref_key_should_show_default_browser_notification</string>
+    <string name="pref_key_is_first_run" translatable="false">pref_key_is_first_run</string>
 
     <!-- Data Choices -->
     <string name="pref_key_telemetry" translatable="false">pref_key_telemetry</string>