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

content/renderer/presentation/presentation_dispatcher.h

Index: content/renderer/presentation/presentation_dispatcher.h
diff --git a/content/renderer/presentation/presentation_dispatcher.h b/content/renderer/presentation/presentation_dispatcher.h
index fb6b4d9a83b02147194dd362b33dc6e1ef65fec0..7a29f46c951c62d48ce905281f0dee8da9c91559 100644
--- a/content/renderer/presentation/presentation_dispatcher.h
+++ b/content/renderer/presentation/presentation_dispatcher.h
@@ -6,7 +6,9 @@
 #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_message.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"
@@ -27,6 +29,7 @@ class CONTENT_EXPORT PresentationDispatcher
   ~PresentationDispatcher() override;
 
  private:
+
   // WebPresentationClient implementation.
   virtual void setController(
       blink::WebPresentationController* controller);
@@ -39,12 +42,25 @@ class CONTENT_EXPORT PresentationDispatcher
       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 uint8* data,
+      size_t length);
   virtual void closeSession(
       const blink::WebString& presentationUrl,
       const blink::WebString& presentationId);
 
-  // RenderFrameObserver
+  // RenderFrameObserver implementation.
   void DidChangeDefaultPresentation() override;
+  void DidCommitProvisionalLoad(
+      bool is_new_navigation,
+      bool is_same_page_navigation) override;
+  void FrameWillClose() override;
 
   void OnScreenAvailabilityChanged(
       const std::string& presentation_url,
@@ -65,9 +81,17 @@ class CONTENT_EXPORT PresentationDispatcher
       const std::string& presentation_url,
       bool watched);
 
+  void DoSendMessage(const MessageRequest& message_request);
+  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