Stub out initial NavigationController browser implementation

content/browser/nav_controller/nav_controller_dispatcher_host.cc

+// Copyright 2013 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 "content/browser/nav_controller/nav_controller_dispatcher_host.h"
+
+#include "content/browser/nav_controller/nav_controller_context.h"
+#include "content/common/nav_controller/nav_controller_messages.h"
+#include "ipc/ipc_message_macros.h"
+#include "url/gurl.h"
+
+namespace content {
+
+NavControllerDispatcherHost::NavControllerDispatcherHost(
+    NavControllerContext* context)
+    : context_(context) {}
+
+NavControllerDispatcherHost::~NavControllerDispatcherHost() {}
+
+bool NavControllerDispatcherHost::OnMessageReceived(const IPC::Message& message,
+                                                    bool* message_was_ok) {
+
+  if (IPC_MESSAGE_CLASS(message) != NavControllerMsgStart)
+    return false;
+
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_EX(
+      NavControllerDispatcherHost, message, *message_was_ok)
+  IPC_MESSAGE_HANDLER(NavControllerHostMsg_RegisterController,
+                      OnRegisterController)
+  IPC_MESSAGE_HANDLER(NavControllerHostMsg_UnregisterController,
+                      OnUnregisterController)
+  IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+
+  return handled;
+}
+
+void NavControllerDispatcherHost::OnRegisterController(int32 registry_id,
+                                                       const string16& scope,
+                                                       const GURL& script_url) {
+}

[Tom Sepez, 2013/09/13 21:48:34]

Are there constraints on what the script_url can be relative to the site
instance that is requesting to add a controller?  If so, please put a comment
here about that so that when you later go to implement it, someone will know to
check for this carefully.  Thanks.

[michaeln, 2013/09/13 22:00:02]

Actually this is a good example of why it's useful to have some context about
the Document from which this request to register something came from. I think it
would be good to set that context up in the initial CLs. I wish i had the
opportunity to make that comment in the Blink CL.

+
+void NavControllerDispatcherHost::OnUnregisterController(
+    int32 registry_id,
+    const string16& scope) {}
+
+}  // namespace content