[Presentation API] 1-UA: send message between controller and receiver page

content/renderer/presentation/presentation_dispatcher.cc

Index: content/renderer/presentation/presentation_dispatcher.cc
diff --git a/content/renderer/presentation/presentation_dispatcher.cc b/content/renderer/presentation/presentation_dispatcher.cc
index a0b3125568cfa47217c6424ab470549d34f99c92..2dafd9566aaec6c524c50049049ed7baefd34bc6 100644
--- a/content/renderer/presentation/presentation_dispatcher.cc
+++ b/content/renderer/presentation/presentation_dispatcher.cc
@@ -81,8 +81,8 @@ namespace content {
 PresentationDispatcher::PresentationDispatcher(RenderFrame* render_frame)
     : RenderFrameObserver(render_frame),
       controller_(nullptr),
-      binding_(this) {
-}
+      receiver_(nullptr),
+      binding_(this) {}
 
 PresentationDispatcher::~PresentationDispatcher() {
   // Controller should be destroyed before the dispatcher when frame is
@@ -435,7 +435,11 @@ void PresentationDispatcher::OnConnectionClosed(
 void PresentationDispatcher::OnSessionMessagesReceived(
     blink::mojom::PresentationSessionInfoPtr session_info,
     std::vector<blink::mojom::SessionMessagePtr> messages) {
-  if (!controller_)
+  auto observer =
+      (receiver_
+           ? static_cast<blink::WebPresentationMessageObserver*>(receiver_)
+           : static_cast<blink::WebPresentationMessageObserver*>(controller_));
+  if (!observer)
     return;
 
   for (size_t i = 0; i < messages.size(); ++i) {
@@ -446,7 +450,7 @@ void PresentationDispatcher::OnSessionMessagesReceived(
     switch (messages[i]->type) {
       case blink::mojom::PresentationMessageType::TEXT: {
         // TODO(mfoltz): Do we need to DCHECK(messages[i]->message)?
-        controller_->didReceiveSessionTextMessage(
+        observer->didReceiveSessionTextMessage(
             session_client.release(),
             blink::WebString::fromUTF8(messages[i]->message.value()));
         break;
@@ -454,9 +458,9 @@ void PresentationDispatcher::OnSessionMessagesReceived(
       case blink::mojom::PresentationMessageType::ARRAY_BUFFER:
       case blink::mojom::PresentationMessageType::BLOB: {
         // TODO(mfoltz): Do we need to DCHECK(messages[i]->data)?
-        controller_->didReceiveSessionBinaryMessage(
-            session_client.release(), &(messages[i]->data->front()),
-            messages[i]->data->size());
+        observer->didReceiveSessionBinaryMessage(session_client.release(),
+                                                 &(messages[i]->data->front()),
+                                                 messages[i]->data->size());
         break;
       }
       default: {