[PresentationAPI] on-session-message handler for ArrayBuffer and Blob messages.

content/renderer/presentation/presentation_dispatcher.cc

 // 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.
 
 #include "content/renderer/presentation/presentation_dispatcher.h"
 
 #include "base/logging.h"
 #include "content/common/presentation/presentation_service.mojom.h"
 #include "content/public/common/presentation_constants.h"
 #include "content/public/common/service_registry.h"
@@ skipping 351 matching lines @@
       GetWebPresentationSessionStateFromMojo(session_state));
 }
 
 void PresentationDispatcher::OnSessionMessagesReceived(
     mojo::Array<presentation::SessionMessagePtr> messages) {
   // When messages is null, there is an error at presentation service side.
   if (!controller_ || messages.is_null())
     return;
 
   for (size_t i = 0; i < messages.size(); ++i) {
-    if (messages[i]->type ==
-        presentation::PresentationMessageType::PRESENTATION_MESSAGE_TYPE_TEXT) {
-      controller_->didReceiveSessionTextMessage(
-          new PresentationSessionClient(messages[i]->presentation_url,
-                                        messages[i]->presentation_id),
-          blink::WebString::fromUTF8(messages[i]->message));
-    } else {
-      // TODO(haibinlu): handle binary message
+    scoped_ptr<PresentationSessionClient> session_client(
+        new PresentationSessionClient(messages[i]->presentation_url,

[mark a. foltz, 2015/06/29 22:21:28]

It appears that this ctor will copy the contents of presentation_url and
presentation_id into a blink::WebString each time through this loop.  Then look
up the PresentationSession to dispatch the event in Presentation.cpp.

This is not ideal from an efficiency point of view, but it's likely that there
will only be one message in the queue, and there is only one active session per
frame.  As this can be optimized later, can you add a NOTE that passing batches
of messages to the Blink layer would be more efficient?

+                                      messages[i]->presentation_id));
+    switch (messages[i]->type) {
+      case presentation::PresentationMessageType::
+          PRESENTATION_MESSAGE_TYPE_TEXT: {
+        controller_->didReceiveSessionTextMessage(
+            session_client.release(),
+            blink::WebString::fromUTF8(messages[i]->message));
+        break;
+      }
+      case presentation::PresentationMessageType::
+          PRESENTATION_MESSAGE_TYPE_ARRAY_BUFFER: {
+        controller_->didReceiveSessionArrayBufferMessage(
+            session_client.release(), &(messages[i]->data.front()),
+            messages[i]->data.size());
+        break;
+      }
+      case presentation::PresentationMessageType::
+          PRESENTATION_MESSAGE_TYPE_BLOB: {
+        controller_->didReceiveSessionBlobMessage(session_client.release(),
+                                                  &(messages[i]->data.front()),
+                                                  messages[i]->data.size());
+        break;
+      }
+      default: {
+        NOTREACHED();
+        break;
+      }
     }
   }
 
   presentation_service_->ListenForSessionMessages(
       base::Bind(&PresentationDispatcher::OnSessionMessagesReceived,
                  base::Unretained(this)));
 }
 
 void PresentationDispatcher::ConnectToPresentationServiceIfNeeded() {
   if (presentation_service_.get())
@@ skipping 14 matching lines @@
   presentation_service_->ListenForSessionStateChange(base::Bind(
       &PresentationDispatcher::OnSessionStateChange,
       base::Unretained(this)));
   presentation_service_->ListenForSessionMessages(
       base::Bind(&PresentationDispatcher::OnSessionMessagesReceived,
       base::Unretained(this)));
   */
 }
 
 }  // namespace content