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 a58ddcc8f6e79d3288d0c645875c8b1bbdaaf209..1283bd18cce78bc5eaad71b3fad01031b54d1ab3 100644
--- a/third_party/blink/public/web/web_message_port_converter.h
+++ b/third_party/blink/public/web/web_message_port_converter.h
@@ -13,6 +13,7 @@ class Isolate;
 template <class T>
 class Local;
 class Value;
+class Context;
 }  // namespace v8
 
 namespace blink {
@@ -25,6 +26,9 @@ 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..10ea1b43e5caa7c6c0f6c9ff5182a712ca422f9b 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 ToV8(port, context->Global(), context->GetIsolate());
+}
+
 }  // namespace blink