[PresentationAPI] Implementing send() from WebPresentationClient to the PresentationService.

content/renderer/presentation/presentation_dispatcher.h

 // 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.
 
 #ifndef CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_
 #define CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_
 
 #include "base/compiler_specific.h"
+#include "base/memory/linked_ptr.h"
 #include "content/common/content_export.h"
 #include "content/common/presentation/presentation_service.mojom.h"
 #include "content/public/renderer/render_frame_observer.h"
 #include "third_party/WebKit/public/platform/modules/presentation/WebPresentationClient.h"
 
 namespace blink {
 class WebString;
 }  // namespace blink
 
 namespace content {
 
 // PresentationDispatcher is a delegate for Presentation API messages used by
 // Blink. It forwards the calls to the Mojo PresentationService.
 class CONTENT_EXPORT PresentationDispatcher
     : public RenderFrameObserver,
       public NON_EXPORTED_BASE(blink::WebPresentationClient) {
  public:
   explicit PresentationDispatcher(RenderFrame* render_frame);
   ~PresentationDispatcher() override;
 
  private:
+
+  // send request from a presentation session.
+  struct CONTENT_EXPORT MessageRequest {
+    MessageRequest(const std::string& presentation_url,
+                   const std::string& presentation_id,
+                   const std::string& message);
+    ~MessageRequest();
+
+    const std::string presentation_url;
+    const std::string presentation_id;
+    const std::string message;
+    // TODO(s.singapati): Handle ArrayBuffer/View and Blob data.
+  };
+
   // WebPresentationClient implementation.
   virtual void setController(
       blink::WebPresentationController* controller);
   virtual void updateAvailableChangeWatched(bool watched);
   virtual void startSession(
       const blink::WebString& presentationUrl,
       const blink::WebString& presentationId,
       blink::WebPresentationSessionClientCallbacks* callback);
   virtual void joinSession(
       const blink::WebString& presentationUrl,
       const blink::WebString& presentationId,
       blink::WebPresentationSessionClientCallbacks* callback);
+  virtual void sendString(
+      const blink::WebString& presentationUrl,
+      const blink::WebString& presentationId,
+      const blink::WebString& message);
+  virtual void sendArrayBuffer(
+      const blink::WebString& presentationUrl,
+      const blink::WebString& presentationId,
+      const char* data,
+      size_t length);
   virtual void closeSession(
       const blink::WebString& presentationUrl,
       const blink::WebString& presentationId);
 
   // RenderFrameObserver
   void DidChangeDefaultPresentation() override;
+  void FrameWillClose() override;
 
   void OnScreenAvailabilityChanged(
       const std::string& presentation_url,
       bool available);
   void OnSessionCreated(
       blink::WebPresentationSessionClientCallbacks* callback,
       presentation::PresentationSessionInfoPtr session_info,
       presentation::PresentationErrorPtr error);
   void OnDefaultSessionStarted(
       presentation::PresentationSessionInfoPtr session_info);
   void OnSessionStateChange(
       presentation::PresentationSessionInfoPtr session_info,
       presentation::PresentationSessionState session_state);
 
   void ConnectToPresentationServiceIfNeeded();
 
   void DoUpdateAvailableChangeWatched(
       const std::string& presentation_url,
       bool watched);
 
+  void DoSendStringMessage(
+      const std::string& presentation_url,
+      const std::string& presentation_id,
+      const std::string& message);
+  void HandleSendMessageRequests();
+
   // Used as a weak reference. Can be null since lifetime is bound to the frame.
   blink::WebPresentationController* controller_;
   presentation::PresentationServicePtr presentation_service_;
+
+  // Message requests are queued here and only one message is sent
+  // at a time over mojo channel.
+  using MessageRequestQueue = std::queue<linked_ptr<MessageRequest>>;
+  MessageRequestQueue message_request_queue_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_