Mojo Channel: Fix deferred proxy dispatch; support paused channels

ipc/ipc_channel_mojo.cc

Index: ipc/ipc_channel_mojo.cc
diff --git a/ipc/ipc_channel_mojo.cc b/ipc/ipc_channel_mojo.cc
index 9948e2dbf220348828c7aaf3f934c67e2ff3b372..80bbfb5627d562803885933a417241d70041ca1b 100644
--- a/ipc/ipc_channel_mojo.cc
+++ b/ipc/ipc_channel_mojo.cc
@@ -282,6 +282,14 @@ ChannelMojo::~ChannelMojo() {
 }
 
 bool ChannelMojo::Connect() {
+  if (!ConnectPaused())
+    return false;
+
+  Unpause(true);
+  return true;
+}
+
+bool ChannelMojo::ConnectPaused() {
   WillConnect();
 
   DCHECK(!task_runner_);
@@ -292,6 +300,22 @@ bool ChannelMojo::Connect() {
   return true;
 }
 
+void ChannelMojo::Unpause(bool flush) {
+  bootstrap_->Start();
+
+  // Ensure that no matter what messages have been queued so far, the first
+  // message we send is always the peer PID.
+  DCHECK(message_reader_);
+  message_reader_->sender()->SetPeerPid(GetSelfPID());
+
+  if (flush)
+    Flush();
+}
+
+void ChannelMojo::Flush() {
+  bootstrap_->Flush();
+}
+
 void ChannelMojo::Close() {
   // NOTE: The MessagePipeReader's destructor may re-enter this function. Use
   // caution when changing this method.
@@ -306,7 +330,6 @@ void ChannelMojo::Close() {
 // MojoBootstrap::Delegate implementation
 void ChannelMojo::OnPipesAvailable(mojom::ChannelAssociatedPtr sender,
                                    mojom::ChannelAssociatedRequest receiver) {
-  sender->SetPeerPid(GetSelfPID());
   message_reader_.reset(new internal::MessagePipeReader(
       pipe_, std::move(sender), std::move(receiver), this));
 }