[PresentationAPI] Implements send API for Blob data from WebPresentationClient

content/common/presentation/presentation_service.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.
 
 module presentation;
 
 struct PresentationSessionInfo {
   string url;
   string id;
 };
@@ skipping 11 matching lines @@
 };
 
 struct PresentationError {
   PresentationErrorType error_type;
   string message;
 };
 
 enum PresentationMessageType {
   TEXT,
   ARRAY_BUFFER,
+  BLOB,
 };
 
 struct SessionMessage {
   string presentation_url;
   string presentation_id;
   PresentationMessageType type;
+  // Used when message type is TEXT.
   string? message;
+  // Used when message type is ARRAY_BUFFER or BLOB.
   array<uint8>? data;
 };
 
 interface PresentationService {
   // Called when the frame sets or changes the default presentation URL or
   // presentation ID.
   SetDefaultPresentationURL(
       string default_presentation_url,
       string? default_presentation_id);
 
@@ skipping 57 matching lines @@
   // Called when the frame is ready to process the next batch of messages.
   // When the callback carries null messages, there is an error
   // at the presentation service side.
   ListenForSessionMessages()
       => (array<SessionMessage>? messages);
 };
 
 interface PresentationServiceClient {
   OnScreenAvailabilityUpdated(bool available);
 };