[Presentation API] reject request.start() with OperationError instead of UnknownError if previous s…

third_party/WebKit/public/platform/modules/presentation/presentation.mojom

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // TODO(crbug.com/647290): Rename "Session" to "Connection"
 
 module blink.mojom;
 
 import "url/mojo/url.mojom";
 
@@ skipping 12 matching lines @@
 enum PresentationConnectionCloseReason {
   CONNECTION_ERROR,
   CLOSED,
   WENT_AWAY
 };
 
 enum PresentationErrorType {
   NO_AVAILABLE_SCREENS,
   SESSION_REQUEST_CANCELLED,
   NO_PRESENTATION_FOUND,
+  PREVIOUS_START_IN_PROGRESS,
   UNKNOWN,
 };
 
 struct PresentationError {
   PresentationErrorType error_type;
   string message;
 };
 
 enum PresentationMessageType {
   TEXT,
@@ skipping 128 matching lines @@
   OnConnectionMessagesReceived(PresentationSessionInfo sessionInfo,
                             array<ConnectionMessage> messages);
 
   // Called on a presentation receiver when presentation connection is available
   // from the controlling page.
   OnReceiverConnectionAvailable(
       PresentationSessionInfo sessionInfo,
       PresentationConnection controller_connection_ptr,
       PresentationConnection& receiver_connection_request);
 };