First use of Nimbus FML plugin (#23400)

* Consume Nimbus FML plugin

* Convert Homescreen to use FML

* Convert nimbusValidation to use FML

* Convert legacy experiments to use the feature API and FML

Remove dead helper code and documentation

* Fixup failing test

Co-authored-by: Grisha Kruglov <gkruglov@mozilla.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

.experimenter.json

@@ -0,0 +1,59 @@
+{
+  "search-term-groups": {
+    "description": "A feature allowing the grouping of URLs around the search term that it came from.",
+    "hasExposure": true,
+    "exposureDescription": "",
+    "variables": {
+      "enabled": {
+        "description": "If true, the feature shows up on the homescreen and on the new tab screen.",
+        "type": "boolean"
+      }
+    }
+  },
+  "default-browser-message": {
+    "description": "A small feature allowing experiments on the placement of a default browser message.",
+    "hasExposure": true,
+    "exposureDescription": "",
+    "variables": {
+      "message-location": {
+        "description": "Where is the message to be put.",
+        "enum": [
+          "homescreen-banner",
+          "settings",
+          "app-menu-item"
+        ],
+        "type": "string"
+      }
+    }
+  },
+  "nimbus-validation": {
+    "description": "A feature that does not correspond to an application feature suitable for showing that Nimbus is working. This should never be used in production.",
+    "hasExposure": true,
+    "exposureDescription": "",
+    "variables": {
+      "settings-icon": {
+        "description": "The drawable displayed in the app menu for Settings",
+        "type": "string"
+      },
+      "settings-punctuation": {
+        "description": "The emoji displayed in the Settings screen title.",
+        "type": "string"
+      },
+      "settings-title": {
+        "description": "The title of displayed in the Settings screen and app menu.",
+        "type": "string"
+      }
+    }
+  },
+  "homescreen": {
+    "description": "The homescreen that the user goes to when they press home or new tab.",
+    "hasExposure": true,
+    "exposureDescription": "",
+    "variables": {
+      "sections-enabled": {
+        "description": "This property provides a lookup table of whether or not the given section should be enabled. If the section is enabled, it should be toggleable in the settings screen, and on by default.",
+        "type": "json"
+      }
+    }
+  }
+}

app/build.gradle

@@ -380,7 +380,28 @@ android.applicationVariants.all { variant ->
 
 // Generate Kotlin code for the Fenix Glean metrics.
 apply plugin: "org.mozilla.telemetry.glean-gradle-plugin"
-
+apply plugin: "org.mozilla.components.nimbus-gradle-plugin"
+
+nimbus {
+    // The path to the Nimbus feature manifest file
+    manifestFile = "nimbus.fml.yaml"
+    // The fully qualified class name for the generated features.
+    // If the classname begins with a '.' this is taken as a suffix to the app's package name
+    destinationClass = ".nimbus.FxNimbus"
+    // Map from the variant name to the channel as experimenter and nimbus understand it.
+    // If nimbus's channels were accurately set up well for this project, then this
+    // shouldn't be needed.
+    channels = [
+            debug: "developer",
+            nightly: "nightly",
+            beta: "beta",
+            release: "release",
+    ]
+    // This is generated by the FML and should be checked into git.
+    // It will be fetched by Experimenter (the Nimbus experiment website)
+    // and used to inform experiment configuration.
+    experimenterManifest = ".experimenter.json"
+}
 configurations {
     // There's an interaction between Gradle's resolution of dependencies with different types
     // (@jar, @aar) for `implementation` and `testImplementation` and with Android Studio's built-in

app/src/main/java/org/mozilla/fenix/FenixApplication.kt

@@ -66,7 +66,6 @@ import org.mozilla.fenix.components.Core
 import org.mozilla.fenix.components.metrics.Event
 import org.mozilla.fenix.components.metrics.MetricServiceType
 import org.mozilla.fenix.components.metrics.MozillaProductDetector
-import org.mozilla.fenix.components.metrics.SecurePrefsTelemetry
 import org.mozilla.fenix.components.toolbar.ToolbarPosition
 import org.mozilla.fenix.ext.isCustomEngine
 import org.mozilla.fenix.ext.isKnownSearchDomain
@@ -273,8 +272,6 @@ open class FenixApplication : LocaleAwareApplication(), Provider {
                             System.currentTimeMillis() - Core.HISTORY_METADATA_MAX_AGE_IN_MS
                         )
                     }
-
-                    SecurePrefsTelemetry(this@FenixApplication, components.analytics.experiments).startTests()
                 }
                 // Account manager initialization needs to happen on the main thread.
                 GlobalScope.launch(Dispatchers.Main) {

app/src/main/java/org/mozilla/fenix/components/Analytics.kt

@@ -23,9 +23,9 @@ import org.mozilla.fenix.ReleaseChannel
 import org.mozilla.fenix.components.metrics.AdjustMetricsService
 import org.mozilla.fenix.components.metrics.GleanMetricsService
 import org.mozilla.fenix.components.metrics.MetricController
-import org.mozilla.fenix.experiments.NimbusFeatures
 import org.mozilla.fenix.experiments.createNimbus
 import org.mozilla.fenix.ext.settings
+import org.mozilla.fenix.nimbus.FxNimbus
 import org.mozilla.fenix.perf.lazyMonitored
 import org.mozilla.geckoview.BuildConfig.MOZ_APP_BUILDID
 import org.mozilla.geckoview.BuildConfig.MOZ_APP_VENDOR
@@ -109,11 +109,9 @@ class Analytics(
     }
 
     val experiments: NimbusApi by lazyMonitored {
-        createNimbus(context, BuildConfig.NIMBUS_ENDPOINT)
-    }
-
-    val features: NimbusFeatures by lazyMonitored {
-        NimbusFeatures(context)
+        createNimbus(context, BuildConfig.NIMBUS_ENDPOINT).also { api ->
+            FxNimbus.api = api
+        }
     }
 }
 

app/src/main/java/org/mozilla/fenix/components/toolbar/DefaultToolbarMenu.kt

@@ -37,11 +37,10 @@ import mozilla.components.support.ktx.android.content.getColorFromAttr
 import mozilla.components.support.ktx.kotlinx.coroutines.flow.ifAnyChanged
 import org.mozilla.fenix.R
 import org.mozilla.fenix.components.accounts.FenixAccountManager
-import org.mozilla.fenix.experiments.ExperimentBranch
-import org.mozilla.fenix.experiments.FeatureId
 import org.mozilla.fenix.ext.components
 import org.mozilla.fenix.ext.settings
-import org.mozilla.fenix.ext.withExperiment
+import org.mozilla.fenix.nimbus.FxNimbus
+import org.mozilla.fenix.nimbus.MessageSurfaceId
 import org.mozilla.fenix.theme.ThemeManager
 import org.mozilla.fenix.utils.BrowsersCache
 
@@ -361,6 +360,7 @@ open class DefaultToolbarMenu(
 
     @VisibleForTesting(otherwise = PRIVATE)
     val coreMenuItems by lazy {
+        val defaultBrowserItem = getSetDefaultBrowserItem()
         val menuItems =
             listOfNotNull(
                 if (shouldUseBottomToolbar) null else menuToolbar,
@@ -372,8 +372,8 @@ open class DefaultToolbarMenu(
                 extensionsItem,
                 syncMenuItem,
                 BrowserMenuDivider(),
-                getSetDefaultBrowserItem(),
-                getSetDefaultBrowserItem()?.let { BrowserMenuDivider() },
+                defaultBrowserItem,
+                defaultBrowserItem?.let { BrowserMenuDivider() },
                 findInPageItem,
                 desktopSiteItem,
                 customizeReaderView.apply { visible = ::shouldShowReaderViewCustomization },
@@ -446,23 +446,17 @@ open class DefaultToolbarMenu(
         }
     }
 
-    private fun getSetDefaultBrowserItem(): BrowserMenuImageText? {
-        val experiments = context.components.analytics.experiments
-        val browsers = BrowsersCache.all(context)
-
-        return experiments.withExperiment(FeatureId.DEFAULT_BROWSER) { experimentBranch ->
-            if (experimentBranch == ExperimentBranch.DEFAULT_BROWSER_TOOLBAR_MENU &&
-                !browsers.isFirefoxDefaultBrowser
+    private fun getSetDefaultBrowserItem(): BrowserMenuImageText? =
+        if (BrowsersCache.all(context).isFirefoxDefaultBrowser) {
+            null
+        } else if (FxNimbus.features.defaultBrowserMessage.value().messageLocation == MessageSurfaceId.APP_MENU_ITEM) {
+            BrowserMenuImageText(
+                label = context.getString(R.string.preferences_set_as_default_browser),
+                imageResource = R.mipmap.ic_launcher
             ) {
-                return@withExperiment BrowserMenuImageText(
-                    label = context.getString(R.string.preferences_set_as_default_browser),
-                    imageResource = R.mipmap.ic_launcher
-                ) {
-                    onItemTapped.invoke(ToolbarMenu.Item.SetDefaultBrowser)
-                }
-            } else {
-                null
+                onItemTapped.invoke(ToolbarMenu.Item.SetDefaultBrowser)
             }
+        } else {
+            null
         }
-    }
 }