Revert of [Presentation API / Media Router] Clean up default pres URL logic.

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 5d20a311e0927bab74e7b86d85622fb8f613ee2b..dd5203dce31567a3007fc996485817fb88235e61 100644
--- a/content/browser/presentation/presentation_service_impl.cc
+++ b/content/browser/presentation/presentation_service_impl.cc
@@ -224,6 +224,13 @@
   screen_availability_listeners_.erase(listener_it);
 }
 
+void PresentationServiceImpl::ListenForDefaultSessionStart(
+    const DefaultSessionMojoCallback& callback) {
+  if (!default_session_start_context_.get())
+    default_session_start_context_.reset(new DefaultSessionStartContext);
+  default_session_start_context_->AddCallback(callback);
+}
+
 void PresentationServiceImpl::StartSession(
     const mojo::String& presentation_url,
     const NewSessionMojoCallback& callback) {
@@ -361,12 +368,11 @@
   const std::string& new_default_url = url.get();
   if (default_presentation_url_ == new_default_url)
     return;
-
+  delegate_->SetDefaultPresentationUrl(
+      render_process_id_,
+      render_frame_id_,
+      new_default_url);
   default_presentation_url_ = new_default_url;
-  delegate_->SetDefaultPresentationUrl(
-      render_process_id_, render_frame_id_, new_default_url,
-      base::Bind(&PresentationServiceImpl::OnDefaultPresentationStarted,
-                 weak_factory_.GetWeakPtr()));
 }
 
 void PresentationServiceImpl::SendSessionMessage(
@@ -515,6 +521,8 @@
 
   pending_join_session_cbs_.clear();
 
+  default_session_start_context_.reset();
+
   if (on_session_messages_callback_.get()) {
     on_session_messages_callback_->Run(
         mojo::Array<presentation::SessionMessagePtr>());
@@ -536,10 +544,9 @@
 }
 
 void PresentationServiceImpl::OnDefaultPresentationStarted(
-    const PresentationSessionInfo& session_info) {
-  DCHECK(client_.get());
-  client_->OnDefaultSessionStarted(
-      presentation::PresentationSessionInfo::From(session_info));
+    const PresentationSessionInfo& session) {
+  if (default_session_start_context_.get())
+    default_session_start_context_->set_session(session);
 }
 
 PresentationServiceImpl::ScreenAvailabilityListenerImpl
@@ -590,4 +597,45 @@
   callback_.reset();
 }
 
+PresentationServiceImpl::DefaultSessionStartContext
+::DefaultSessionStartContext() {
+}
+
+PresentationServiceImpl::DefaultSessionStartContext
+::~DefaultSessionStartContext() {
+  Reset();
+}
+
+void PresentationServiceImpl::DefaultSessionStartContext::AddCallback(
+    const DefaultSessionMojoCallback& callback) {
+  if (session_.get()) {
+    DCHECK(callbacks_.empty());
+    callback.Run(presentation::PresentationSessionInfo::From(*session_));
+    session_.reset();
+  } else {
+    callbacks_.push_back(new DefaultSessionMojoCallback(callback));
+  }
+}
+
+void PresentationServiceImpl::DefaultSessionStartContext::set_session(
+    const PresentationSessionInfo& session) {
+  if (callbacks_.empty()) {
+    session_.reset(new PresentationSessionInfo(session));
+  } else {
+    DCHECK(!session_.get());
+    ScopedVector<DefaultSessionMojoCallback> callbacks;
+    callbacks.swap(callbacks_);
+    for (const auto& callback : callbacks)
+      callback->Run(presentation::PresentationSessionInfo::From(session));
+  }
+}
+
+void PresentationServiceImpl::DefaultSessionStartContext::Reset() {
+  ScopedVector<DefaultSessionMojoCallback> callbacks;
+  callbacks.swap(callbacks_);
+  for (const auto& callback : callbacks)
+    callback->Run(presentation::PresentationSessionInfoPtr());
+  session_.reset();
+}
+
 }  // namespace content