Analytics: add screen API

vector/src/main/java/im/vector/app/features/analytics/VectorAnalytics.kt

@@ -63,4 +63,9 @@ interface VectorAnalytics {
      * Capture an Event
      */
     fun capture(event: String, properties: Map<String, Any>? = null)
+
+    /**
+     * Track a displayed screen
+     */
+    fun screen(name: String, properties: Map<String, Any>? = null)
 }

vector/src/main/java/im/vector/app/features/analytics/impl/DefaultVectorAnalytics.kt

@@ -93,11 +93,22 @@ class DefaultVectorAnalytics @Inject constructor(
     override fun capture(event: String, properties: Map<String, Any>?) {
         posthog?.capture(
                 event,
-                properties?.let { props ->
-                    Properties().apply {
-                        props.forEach { putValue(it.key, it.value) }
-                    }
-                }
+                properties.toPostHogProperties()
         )
     }
+
+    override fun screen(name: String, properties: Map<String, Any>?) {
+        posthog?.screen(
+                name,
+                properties.toPostHogProperties()
+        )
+    }
+
+    private fun Map<String, Any>?.toPostHogProperties(): Properties? {
+        if (this == null) return null
+
+        return Properties().apply {
+            this@toPostHogProperties.forEach { putValue(it.key, it.value) }
+        }
+    }
 }