Adds plumbing to pass WebUI mojo::Handle from browser to renderer

content/renderer/mojo/mojo_render_process_observer.cc

 // Copyright 2014 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/renderer/mojo/mojo_render_process_observer.h"
 
 #include "base/message_loop/message_loop.h"
 #include "content/child/child_process.h"
 #include "content/common/mojo/mojo_channel_init.h"
 #include "content/common/mojo/mojo_messages.h"
 #include "content/public/renderer/render_thread.h"
+#include "content/public/renderer/render_view.h"
+#include "content/renderer/web_ui_mojo.h"
 
 namespace content {
 
 MojoRenderProcessObserver::MojoRenderProcessObserver(
     RenderThread* render_thread)
     : render_thread_(render_thread) {
   render_thread_->AddObserver(this);
 }
 
 bool MojoRenderProcessObserver::OnControlMessageReceived(
@@ skipping 17 matching lines @@
 void MojoRenderProcessObserver::OnChannelCreated(
     const IPC::PlatformFileForTransit& file) {
 #if defined(OS_POSIX)
   base::PlatformFile handle = file.fd;
 #elif defined(OS_WIN)
   base::PlatformFile handle = file;
 #endif
   DCHECK(!channel_init_.get());
   channel_init_.reset(new MojoChannelInit);
   channel_init_->Init(handle, ChildProcess::current()->io_message_loop_proxy());
+  if (!channel_init_->is_handle_valid())
+    return;

[darin (slow to review), 2014/03/21 00:04:52]

should there be an assertion here if the handle is not valid?

[sky, 2014/03/21 03:19:16]

I think you're suggesting to make this a DCHECK, right? It's possible
initialization could fail though for valid reasons, right? In which case we
don't want to crash.

+
+  ScopedRenderProcessHostMojoHandle render_process_host_handle(
+      RenderProcessHostMojoHandle(
+          channel_init_->bootstrap_message_pipe().release().value()));
+  render_process_host_mojo_.reset(render_process_host_handle.Pass(), this);
+}
+
+void MojoRenderProcessObserver::SetBrowserWebUIHandle(

[darin (slow to review), 2014/03/21 00:04:52]

I see why the view ID is needed now. Hmm, OK. Long term, we'll probably have a
mojo MessagePipe per RenderView (or per RenderFrame), and in that world, we'd be
passing this Handle over that message pipe.

[sky, 2014/03/21 03:19:16]

I agree. Long term it seems like we'll want an interface per RenderView, but I
was hesitant to plumb all of that right now.

+    int32 view_routing_id,
+    mojo::ScopedHandle web_ui_handle) {
+  RenderView* render_view = RenderView::FromRoutingID(view_routing_id);
+  if (!render_view)
+    return;
+  WebUIMojo* web_ui_mojo = WebUIMojo::Get(render_view);
+  if (!web_ui_mojo)
+    return;
+  web_ui_mojo->SetBrowserHandle(web_ui_handle.Pass());
 }
 
 }  // namespace content