[Extensions] Begin making Extension port initialization asynchronous

extensions/renderer/extension_port.cc

Index: extensions/renderer/extension_port.cc
diff --git a/extensions/renderer/extension_port.cc b/extensions/renderer/extension_port.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7ba4571ddc3cd0546cdbdb613f42b7d72dcce24a
--- /dev/null
+++ b/extensions/renderer/extension_port.cc
@@ -0,0 +1,64 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "extensions/renderer/extension_port.h"
+
+#include "content/public/renderer/render_frame.h"
+#include "extensions/common/api/messaging/message.h"
+#include "extensions/common/extension_messages.h"
+#include "extensions/renderer/script_context.h"
+
+namespace extensions {
+
+ExtensionPort::ExtensionPort(ScriptContext* script_context, int local_id)
+    : script_context_(script_context), local_id_(local_id) {}
+
+ExtensionPort::~ExtensionPort() {}
+
+void ExtensionPort::SetGlobalId(int id) {
+  global_id_ = id;
+  content::RenderFrame* render_frame = script_context_->GetRenderFrame();
+  for (const auto& message : pending_messages_)
+    PostMessageImpl(render_frame, *message);
+  if (is_disconnected_)
+    SendDisconnected(render_frame);
+  pending_messages_.clear();
+}
+
+void ExtensionPort::PostExtensionMessage(std::unique_ptr<Message> message) {
+  if (!initialized()) {
+    pending_messages_.push_back(std::move(message));
+    return;
+  }
+  PostMessageImpl(script_context_->GetRenderFrame(), *message);
+}
+
+void ExtensionPort::Close(bool close_channel) {
+  is_disconnected_ = true;
+  close_channel_ = close_channel;
+  if (!initialized())
+    return;
+
+  SendDisconnected(script_context_->GetRenderFrame());
+}
+
+void ExtensionPort::PostMessageImpl(content::RenderFrame* render_frame,
+                                    const Message& message) {
+  // TODO(devlin): What should we do if there's no render frame? Up until now,
+  // we've always just dropped the messages, but we might need to figure this
+  // out for service workers.
+  if (!render_frame)
+    return;
+  render_frame->Send(new ExtensionHostMsg_PostMessage(
+      render_frame->GetRoutingID(), global_id_, message));
+}
+
+void ExtensionPort::SendDisconnected(content::RenderFrame* render_frame) {
+  if (!render_frame)
+    return;
+  render_frame->Send(new ExtensionHostMsg_CloseMessagePort(
+      render_frame->GetRoutingID(), global_id_, close_channel_));
+}
+
+}  // namespace extensions