Add digital asset linking snippets (#476)

Author: cy245

identity/credentialmanager/src/main/digitalAssetLinking/assetlinks.json

@@ -0,0 +1,33 @@
+/*
+ * 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.
+ */
+
+// [START android_identity_assetlinks_json]
+[
+  {
+    "relation" : [
+      "delegate_permission/common.handle_all_urls",
+      "delegate_permission/common.get_login_creds"
+    ],
+    "target" : {
+      "namespace" : "android_app",
+      "package_name" : "com.example.android",
+      "sha256_cert_fingerprints" : [
+        SHA_HEX_VALUE
+      ]
+    }
+  }
+]
+// [END android_identity_assetlinks_json]

identity/credentialmanager/src/main/digitalAssetLinking/othersnippets

@@ -0,0 +1,45 @@
+/*
+ * 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.
+ */
+
+// Enable host to permit Google to retrieve the DAL
+// [START android_identity_assetlinks_allow_host]
+User-agent: *
+Allow: /.well-known/
+// [END android_identity_assetlinks_allow_host]
+
+// Manifest file addition
+// [START android_identity_assetlinks_manifest]
+<meta-data android:name="asset_statements" android:resource="@string/asset_statements" />
+// [END android_identity_assetlinks_manifest]
+
+// Declare association in Android app
+// [START android_identity_assetlinks_app_association]
+<string name="asset_statements" translatable="false">
+[{
+  \"include\": \"https://signin.example.com/.well-known/assetlinks.json\"
+}]
+</string>
+// [END android_identity_assetlinks_app_association]
+
+// Example status code to test DAL
+// [START android_identity_assetlinks_curl_check]
+> GET /.well-known/assetlinks.json HTTP/1.1
+> User-Agent: curl/7.35.0
+> Host: signin.example.com
+
+< HTTP/1.1 200 OK
+< Content-Type: application/json
+// [END android_identity_assetlinks_curl_check]