Implement the close() API for Message ports

The close API has to consider these cases:
1. A message port can be in a pending state
2. A message could be queued in renderer waiting for conversion

Therefore close() immediately closes the port, but it does not
cleanup the resources until all the messages are transferred.

BUG=393291

Review URL: https://codereview.chromium.org/956763002

Cr-Commit-Position: refs/heads/master@{#318271}

1 files changed, 7 insertions, 0 deletions

diff --git a/content/browser/message_port_provider.cc b/content/browser/message_port_provider.cc
index fac53a9..ac329bc 100644
--- a/content/browser/message_port_provider.cc
+++ b/content/browser/message_port_provider.cc
@@ -90,6 +90,13 @@ void MessagePortProvider::PostMessageToPort(
 }
 
 // static
+void MessagePortProvider::ClosePort(int message_port_id) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  MessagePortService* msp = MessagePortService::GetInstance();
+  msp->ClosePort(message_port_id);
+}
+
+// static
 void MessagePortProvider::OnMessagePortDelegateClosing(
     MessagePortDelegate* delegate) {
   MessagePortService::GetInstance()->OnMessagePortDelegateClosing(delegate);