feat: adds external account authorized user credentials (#1129)

* feat: adds external account authorized user credentials

* fix: positioning

* fix: serialVersionUID

* fix: toString() test

* fix: tests

Author: lsirac

oauth2_http/java/com/google/auth/oauth2/ExternalAccountAuthorizedUserCredentials.java

@@ -181,6 +181,10 @@ public static GoogleCredentials fromStream(
     if (ExternalAccountCredentials.EXTERNAL_ACCOUNT_FILE_TYPE.equals(fileType)) {
       return ExternalAccountCredentials.fromJson(fileContents, transportFactory);
     }
+    if (ExternalAccountAuthorizedUserCredentials.EXTERNAL_ACCOUNT_AUTHORIZED_USER_FILE_TYPE.equals(
+        fileType)) {
+      return ExternalAccountAuthorizedUserCredentials.fromJson(fileContents, transportFactory);
+    }
     if ("impersonated_service_account".equals(fileType)) {
       return ImpersonatedCredentials.fromJson(fileContents, transportFactory);
     }

oauth2_http/java/com/google/auth/oauth2/GoogleCredentials.java

@@ -33,6 +33,10 @@
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
+import com.google.api.client.http.HttpResponseException;
+import com.google.api.client.json.GenericJson;
+import com.google.api.client.json.JsonParser;
+import java.io.IOException;
 import javax.annotation.Nullable;
 
 /**
@@ -77,4 +81,21 @@ String getErrorDescription() {
   String getErrorUri() {
     return errorUri;
   }
+
+  static OAuthException createFromHttpResponseException(HttpResponseException e)
+      throws IOException {
+    JsonParser parser = OAuth2Utils.JSON_FACTORY.createJsonParser((e).getContent());
+    GenericJson errorResponse = parser.parseAndClose(GenericJson.class);
+
+    String errorCode = (String) errorResponse.get("error");
+    String errorDescription = null;
+    String errorUri = null;
+    if (errorResponse.containsKey("error_description")) {
+      errorDescription = (String) errorResponse.get("error_description");
+    }
+    if (errorResponse.containsKey("error_uri")) {
+      errorUri = (String) errorResponse.get("error_uri");
+    }
+    return new OAuthException(errorCode, errorDescription, errorUri);
+  }
 }

oauth2_http/java/com/google/auth/oauth2/OAuthException.java

@@ -107,17 +107,7 @@ public StsTokenExchangeResponse exchangeToken() throws IOException {
       GenericData responseData = response.parseAs(GenericData.class);
       return buildResponse(responseData);
     } catch (HttpResponseException e) {
-      GenericJson errorResponse = parseJson((e).getContent());
-      String errorCode = (String) errorResponse.get("error");
-      String errorDescription = null;
-      String errorUri = null;
-      if (errorResponse.containsKey("error_description")) {
-        errorDescription = (String) errorResponse.get("error_description");
-      }
-      if (errorResponse.containsKey("error_uri")) {
-        errorUri = (String) errorResponse.get("error_uri");
-      }
-      throw new OAuthException(errorCode, errorDescription, errorUri);
+      throw OAuthException.createFromHttpResponseException(e);
     }
   }