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

content/browser/presentation/presentation_service_impl.cc

Index: content/browser/presentation/presentation_service_impl.cc
diff --git a/content/browser/presentation/presentation_service_impl.cc b/content/browser/presentation/presentation_service_impl.cc
index 6b62c5f509bd50fe01cd5882fac0e8b715e68065..f1b85371799543820da88636ed0df2de0ea9e1a9 100644
--- a/content/browser/presentation/presentation_service_impl.cc
+++ b/content/browser/presentation/presentation_service_impl.cc
@@ -19,6 +19,8 @@
 
 namespace {
 
+static const size_t kMaxPresentationSessionMessageSize = 64 * 1024; // 64 KB.
+
 // The return value takes ownership of the contents of |input|.
 presentation::SessionMessagePtr ToMojoSessionMessage(
     content::PresentationSessionMessage* input) {
@@ -39,7 +41,38 @@ presentation::SessionMessagePtr ToMojoSessionMessage(
   return output.Pass();
 }
 
-}  // namespace
+scoped_ptr<content::PresentationSessionMessage> GetPresentationSessionMessage(
+    presentation::SessionMessagePtr input) {
+  DCHECK(!input.is_null());
+  scoped_ptr<content::PresentationSessionMessage> output;
+  if (input->type == presentation::PresentationMessageType::
+                     PRESENTATION_MESSAGE_TYPE_TEXT) {
+    DCHECK(!input->message.is_null());
+    DCHECK_LE(input->message.size(),

[mark a. foltz, 2015/05/07 01:34:30]

Don't we want to validate this in all builds and return a null PSM?

[USE s.singapati at gmail.com, 2015/05/07 14:08:51]

Done. Now it returns null PresentationSessionMessage to delegate.
Added unit test.

+              kMaxPresentationSessionMessageSize);
+    DCHECK(input->data.is_null()); // And size is 0.
+    output = content::PresentationSessionMessage::CreateStringMessage(
+                 input->presentation_url,
+                 input->presentation_id,
+                 scoped_ptr<std::string>(new std::string(input->message)));

[mark a. foltz, 2015/05/07 01:34:30]

Instead of allocating a new string, pass an empty scoped_ptr and have output
take ownership of the input contents as is done above.

output->message.Swap(input.message.get())

[USE s.singapati at gmail.com, 2015/05/07 14:08:51]

swap() can not take input->message.get() which is "const std::string&".

[whywhat, 2015/05/07 14:22:01]

Swap is reflective so you can use input->message.Swap(output->message.get());
If possible (e.g. dependency is allowed) I would pass mojo::String to
createStringMessage so this swapping happens in the function, not afterwards.

+
+  } else if (input->type == presentation::PresentationMessageType::
+              PRESENTATION_MESSAGE_TYPE_ARRAY_BUFFER) {
+    DCHECK(!input->data.is_null());
+    DCHECK_LE(input->data.size(),
+              kMaxPresentationSessionMessageSize);
+    DCHECK(input->message.is_null()); // And size is 0.
+    output = content::PresentationSessionMessage::CreateBinaryMessage(
+                 input->presentation_url,
+                 input->presentation_id,
+                 scoped_ptr<std::vector<uint8_t>>(
+                     new std::vector<uint8_t>(input->data)));

[mark a. foltz, 2015/05/07 01:34:30]

Same comment as above.

[USE s.singapati at gmail.com, 2015/05/07 14:08:51]

swap() can not take input->data.storage() which is "const std::vector<>".

[whywhat, 2015/05/07 14:22:01]

Ditto.

+  }
+
+  return output.Pass();
+}
+
+} // namespace
 
 namespace content {
 
@@ -338,6 +371,37 @@ void PresentationServiceImpl::SetDefaultPresentationURL(
   DoSetDefaultPresentationUrl(new_default_url, default_presentation_id);
 }
 
+
+void PresentationServiceImpl::SendMessage(
+    presentation::SessionMessagePtr session_message,
+    const SendMessageMojoCallback& callback) {
+  DVLOG(2) << "SendMessage";
+  DCHECK(!session_message.is_null());
+  // send_message_cb_ptr_ should be null by now, otherwise resetting of
+  // send_message_cb_ptr_ with new callback will drop the old callback.
+  if (!delegate_ || send_message_cb_ptr_) {
+    callback.Run(false);
+    return;
+  }
+
+  send_message_cb_ptr_.reset(new SendMessageMojoCallback(callback));
+  delegate_->SendMessage(
+      render_process_id_,
+      render_frame_id_,
+      GetPresentationSessionMessage(session_message.Pass()),
+      base::Bind(&PresentationServiceImpl::OnSendMessageCallback,
+                 weak_factory_.GetWeakPtr()));
+}
+
+void PresentationServiceImpl::OnSendMessageCallback() {
+  // It is possible that Reset() is invoked before receiving this callback.
+  // So, always check send_message_cb_ptr_ for non-null.
+  if (send_message_cb_ptr_) {
+    send_message_cb_ptr_->Run(true);
+    send_message_cb_ptr_.reset();
+  }
+}
+
 void PresentationServiceImpl::CloseSession(
     const mojo::String& presentation_url,
     const mojo::String& presentation_id) {
@@ -448,6 +512,12 @@ void PresentationServiceImpl::Reset() {
         mojo::Array<presentation::SessionMessagePtr>());
     on_session_messages_callback_.reset();
   }
+  if (send_message_cb_ptr_) {
+    // Run the callback with false, indicating the renderer to stop sending
+    // the requests and invalidate all pending requests.
+    send_message_cb_ptr_->Run(false);
+    send_message_cb_ptr_.reset();
+  }
 }
 
 // static