Gets presentation ID from route ID upon route creation, and overrides previous presentation ID with…

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 f6527896aa2837af9ebbcf4ba91a26cfa0607cac..bf467e3e4f7dc1ec77b9dc639d3c69dd6e123576 100644
--- a/content/browser/presentation/presentation_service_impl.cc
+++ b/content/browser/presentation/presentation_service_impl.cc
@@ -405,11 +405,11 @@ void PresentationServiceImpl::SendSessionMessage(
                  weak_factory_.GetWeakPtr()));
 }
 
-void PresentationServiceImpl::OnSendMessageCallback() {
+void PresentationServiceImpl::OnSendMessageCallback(bool sent) {
   // It is possible that Reset() is invoked before receiving this callback.
   // So, always check send_message_callback_ for non-null.
   if (send_message_callback_) {
-    send_message_callback_->Run(true);
+    send_message_callback_->Run(sent);
     send_message_callback_.reset();
   }
 }
@@ -457,18 +457,22 @@ void PresentationServiceImpl::ListenForSessionMessages(
 
 void PresentationServiceImpl::OnSessionMessages(
     scoped_ptr<ScopedVector<PresentationSessionMessage>> messages) {
-  DCHECK(messages.get() && !messages->empty());
   if (!on_session_messages_callback_.get()) {
     // The Reset method of this class was invoked.
     return;
   }
 
-  mojo::Array<presentation::SessionMessagePtr> mojoMessages(messages->size());
-  for (size_t i = 0; i < messages->size(); ++i) {
-    mojoMessages[i] = ToMojoSessionMessage((*messages)[i]);
+  if (!messages.get() || messages->empty()) {
+    on_session_messages_callback_->Run(

[Kevin M, 2015/06/24 23:02:07]

Add a comment indicating that branch is an error handler (it took some digging
for me to understand what empty array meant)

[haibinlu, 2015/06/24 23:25:13]

Done.

+        mojo::Array<presentation::SessionMessagePtr>());
+  } else {
+    mojo::Array<presentation::SessionMessagePtr> mojoMessages(messages->size());
+    for (size_t i = 0; i < messages->size(); ++i) {
+      mojoMessages[i] = ToMojoSessionMessage((*messages)[i]);
+    }
+    on_session_messages_callback_->Run(mojoMessages.Pass());
   }
 
-  on_session_messages_callback_->Run(mojoMessages.Pass());
   on_session_messages_callback_.reset();
 }