Switch DRM platform to using a separate thread

ui/ozone/platform/drm/gpu/drm_thread_proxy.cc

Index: ui/ozone/platform/drm/gpu/drm_thread_proxy.cc
diff --git a/ui/ozone/platform/drm/gpu/drm_thread_proxy.cc b/ui/ozone/platform/drm/gpu/drm_thread_proxy.cc
new file mode 100644
index 0000000000000000000000000000000000000000..19442cb096e37a41a9ae2f1ec500e4b4152c029c
--- /dev/null
+++ b/ui/ozone/platform/drm/gpu/drm_thread_proxy.cc
@@ -0,0 +1,33 @@
+// Copyright 2015 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 "ui/ozone/platform/drm/gpu/drm_thread_proxy.h"
+
+#include "base/bind.h"
+#include "ui/ozone/platform/drm/gpu/drm_window_proxy.h"
+#include "ui/ozone/platform/drm/gpu/message_filter_proxy.h"
+#include "ui/ozone/platform/drm/gpu/proxy_helpers.h"
+
+namespace ui {
+
+DrmThreadProxy::DrmThreadProxy() {}
+
+DrmThreadProxy::~DrmThreadProxy() {}
+
+scoped_refptr<MessageFilterProxy> DrmThreadProxy::CreateMessageFilterProxy() {
+  return make_scoped_refptr(new MessageFilterProxy(&drm_thread_));
+}
+
+scoped_ptr<DrmWindowProxy> DrmThreadProxy::CreateDrmWindowProxy(
+    gfx::AcceleratedWidget widget) {
+  // Because the DrmDeviceManager can be used from any thread without posting a
+  // message to the DRM thread, we need to make sure that the DRM thread has
+  // finished processing the window creation message before returning the proxy
+  // otherwise we could start requesting buffer allocations for an unrealized
+  // window.
+  PostSyncTask(drm_thread_.task_runner(), base::Bind(&base::DoNothing));

[spang, 2015/09/30 18:47:31]

Can you do the sync post in CreateNativePixmap instead and make this one async.

I think now that we have a thread we should be able to just get rid of
DrmDeviceManager and just use DrmWindow directly.

[dnicoara, 2015/10/01 14:36:15]

I was talking to alexst@ yesterday and I'll rework the DrmDeviceManager so we
don't need to access it directly (We'll be posting a sync task when allocating
buffers). That'll solve this issue.

+  return make_scoped_ptr(new DrmWindowProxy(widget, &drm_thread_));
+}
+
+}  // namespace ui