RUM-9908 update RUM Scope interface

Author: xgouchet

features/dd-sdk-android-rum/src/main/kotlin/com/datadog/android/rum/internal/domain/scope/RumActionScope.kt

@@ -24,7 +24,7 @@ import java.util.concurrent.TimeUnit
 import kotlin.math.max
 
 internal class RumActionScope(
-    val parentScope: RumScope,
+    override val parentScope: RumScope,
     private val sdkCore: InternalSdkCore,
     val waitForStop: Boolean,
     eventTime: Time,

features/dd-sdk-android-rum/src/main/kotlin/com/datadog/android/rum/internal/domain/scope/RumApplicationScope.kt

@@ -42,6 +42,8 @@ internal class RumApplicationScope(
     private val slowFramesListener: SlowFramesListener?
 ) : RumScope, RumViewChangedListener {
 
+    override val parentScope: RumScope? = null
+
     private var rumContext = RumContext(applicationId = applicationId)
 
     internal val childScopes: MutableList<RumScope> = mutableListOf(

features/dd-sdk-android-rum/src/main/kotlin/com/datadog/android/rum/internal/domain/scope/RumResourceScope.kt

@@ -35,7 +35,7 @@ import java.util.UUID
 
 @Suppress("LongParameterList", "TooManyFunctions")
 internal class RumResourceScope(
-    internal val parentScope: RumScope,
+    override val parentScope: RumScope,
     internal val sdkCore: InternalSdkCore,
     internal val url: String,
     internal val method: RumResourceMethod,

features/dd-sdk-android-rum/src/main/kotlin/com/datadog/android/rum/internal/domain/scope/RumScope.kt

@@ -9,11 +9,12 @@ package com.datadog.android.rum.internal.domain.scope
 import androidx.annotation.WorkerThread
 import com.datadog.android.api.storage.DataWriter
 import com.datadog.android.rum.internal.domain.RumContext
-import com.datadog.tools.annotation.NoOpImplementation
 
 @NoOpImplementation
 internal interface RumScope {
 
+    val parentScope: RumScope?
+
     /**
      * Handles an incoming event.
      * If needed, writes a RumEvent to the provided writer.
@@ -37,6 +38,15 @@ internal interface RumScope {
      */
     fun getRumContext(): RumContext
 
+    /**
+     * @return the custom attributes for this scope (including the parent's scope current attributes)
+     * A given scope's attribute can override a parent scope's attribute.
+     */
+    fun getCustomAttributes(): Map<String, Any?> {
+        // Default implementation, simply returns the parent's attributes
+        return parentScope?.getCustomAttributes() ?: emptyMap()
+    }
+
     companion object {
         internal const val SYNTHETICS_LOGCAT_TAG = "DatadogSynthetics"
     }

features/dd-sdk-android-rum/src/main/kotlin/com/datadog/android/rum/internal/domain/scope/RumSessionScope.kt

@@ -27,7 +27,7 @@ import java.util.concurrent.atomic.AtomicLong
 
 @Suppress("LongParameterList")
 internal class RumSessionScope(
-    private val parentScope: RumScope,
+    override val parentScope: RumScope,
     private val sdkCore: InternalSdkCore,
     private val sessionEndedMetricDispatcher: SessionMetricDispatcher,
     internal val sampleRate: Float,

features/dd-sdk-android-rum/src/main/kotlin/com/datadog/android/rum/internal/domain/scope/RumViewManagerScope.kt

@@ -33,7 +33,7 @@ import java.util.concurrent.TimeUnit
 
 @Suppress("LongParameterList")
 internal class RumViewManagerScope(
-    private val parentScope: RumScope,
+    override val parentScope: RumScope,
     private val sdkCore: InternalSdkCore,
     private val sessionEndedMetricDispatcher: SessionMetricDispatcher,
     private val backgroundTrackingEnabled: Boolean,

features/dd-sdk-android-rum/src/main/kotlin/com/datadog/android/rum/internal/domain/scope/RumViewScope.kt

@@ -54,7 +54,7 @@ import kotlin.math.min
 
 @Suppress("TooManyFunctions", "LargeClass", "LongParameterList")
 internal open class RumViewScope(
-    private val parentScope: RumScope,
+    override val parentScope: RumScope,
     private val sdkCore: InternalSdkCore,
     private val sessionEndedMetricDispatcher: SessionMetricDispatcher,
     internal val key: RumScopeKey,