Added Code Snippets for Decorators (#690)

* Added Code Snippets for Decorators

Author: srikrishnasakunia

compose/snippets/src/main/java/com/example/compose/snippets/navigation3/decorators/DecoratorSnippets.kt

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.compose.snippets.navigation3.decorators
+
+import android.util.Log
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.navigation3.runtime.NavEntryDecorator
+import androidx.navigation3.runtime.NavKey
+import androidx.navigation3.runtime.entryProvider
+import androidx.navigation3.runtime.rememberNavBackStack
+import androidx.navigation3.runtime.rememberSaveableStateHolderNavEntryDecorator
+import androidx.navigation3.ui.NavDisplay
+import com.example.compose.snippets.navigation3.savingstate.Home
+import kotlinx.serialization.Serializable
+
+// [START android_compose_navigation3_decorator_1]
+// import androidx.navigation3.runtime.NavEntryDecorator
+class CustomNavEntryDecorator<T : Any> : NavEntryDecorator<T>(
+    decorate = { entry ->
+        Log.d("CustomNavEntryDecorator", "entry with ${entry.contentKey} entered composition and was decorated")
+        entry.Content()
+    },
+    onPop = { contentKey -> Log.d("CustomNavEntryDecorator", "entry with $contentKey was popped") }
+)
+// [END android_compose_navigation3_decorator_1]
+
+@Serializable
+data object Home : NavKey
+
+@Composable
+fun DecoratorsBasic() {
+    // [START android_compose_navigation3_decorator_2]
+
+    // import androidx.navigation3.runtime.rememberSaveableStateHolderNavEntryDecorator
+    NavDisplay(
+        entryDecorators = listOf(
+            rememberSaveableStateHolderNavEntryDecorator(),
+            remember { CustomNavEntryDecorator() }
+        ),
+        // [START_EXCLUDE]
+        backStack = rememberNavBackStack(Home),
+        entryProvider = entryProvider {
+            entry<Home> { Text("Welcome to Nav3") }
+        }
+        // [END_EXCLUDE]
+    )
+    // [END android_compose_navigation3_decorator_2]
+}