From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jeremy Apthorp <nornagon@nornagon.net>
Date: Fri, 25 Oct 2019 11:23:03 -0700
Subject: add WebMessagePortConverter::EntangleAndInjectMessagePortChannel

This adds a method to the public Blink API that would otherwise require
accessing Blink internals. Its inverse, which already exists, is used in
Android WebView.

diff --git a/third_party/blink/public/web/web_message_port_converter.h b/third_party/blink/public/web/web_message_port_converter.h
index 23b17b4a46a31cb005e36bb1bbadba6cc3ea6b3c..b86862dcf5232fc6971293fe2c9f17c97008a3a7 100644
--- a/third_party/blink/public/web/web_message_port_converter.h
+++ b/third_party/blink/public/web/web_message_port_converter.h
@@ -12,6 +12,7 @@
 namespace v8 {
 class Isolate;
 class Value;
+class Context;
 }  // namespace v8
 
 namespace blink {
@@ -24,6 +25,9 @@ class BLINK_EXPORT WebMessagePortConverter {
   // neutered, it will return nullopt.
   static absl::optional<MessagePortChannel>
   DisentangleAndExtractMessagePortChannel(v8::Isolate*, v8::Local<v8::Value>);
+
+  BLINK_EXPORT static v8::Local<v8::Value>
+  EntangleAndInjectMessagePortChannel(v8::Local<v8::Context>, MessagePortChannel);
 };
 
 }  // namespace blink
diff --git a/third_party/blink/renderer/core/exported/web_message_port_converter.cc b/third_party/blink/renderer/core/exported/web_message_port_converter.cc
index 6a6cb3d4ef0e454d18cf47cd971240d0dabea9fb..bd90d018d5c3e33a41b17b1d015ac25d340f8666 100644
--- a/third_party/blink/renderer/core/exported/web_message_port_converter.cc
+++ b/third_party/blink/renderer/core/exported/web_message_port_converter.cc
@@ -6,6 +6,7 @@
 
 #include "third_party/blink/public/common/messaging/message_port_channel.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_value.h"
+#include "third_party/blink/renderer/bindings/core/v8/v8_binding_for_core.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_message_port.h"
 #include "third_party/blink/renderer/core/messaging/message_port.h"
 
@@ -21,4 +22,15 @@ WebMessagePortConverter::DisentangleAndExtractMessagePortChannel(
   return port->Disentangle();
 }
 
+v8::Local<v8::Value>
+WebMessagePortConverter::EntangleAndInjectMessagePortChannel(
+    v8::Local<v8::Context> context,
+    MessagePortChannel port_channel) {
+  auto* execution_context = ToExecutionContext(context);
+  CHECK(execution_context);
+  auto* port = MakeGarbageCollected<MessagePort>(*execution_context);
+  port->Entangle(std::move(port_channel));
+  return port->ToV8(context->GetIsolate(), context->Global());
+}
+
 }  // namespace blink
