Switch DRM platform to using a separate thread

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

+// 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_window_proxy.h"
+
+#include "ui/ozone/platform/drm/gpu/drm_device.h"
+#include "ui/ozone/platform/drm/gpu/drm_window.h"
+#include "ui/ozone/platform/drm/gpu/hardware_display_controller.h"
+#include "ui/ozone/platform/drm/gpu/proxy_helpers.h"
+#include "ui/ozone/platform/drm/gpu/scanout_buffer.h"
+
+namespace ui {
+
+DrmWindowProxy::DrmWindowProxy(

[spang, 2015/09/14 18:41:43]

Can we merge this with the surface class?

[dnicoara, 2015/09/17 21:58:21]

Done.

+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+    base::WeakPtr<DrmWindow> impl,
+    gfx::AcceleratedWidget widget)
+    : task_runner_(task_runner), impl_(impl), widget_(widget) {}
+
+DrmWindowProxy::~DrmWindowProxy() {}
+
+void DrmWindowProxy::QueueOverlayPlane(const OverlayPlane& plane) const {
+  task_runner_->PostTask(
+      FROM_HERE, base::Bind(&DrmWindow::QueueOverlayPlane, impl_, plane));
+}
+
+bool DrmWindowProxy::SchedulePageFlip(
+    bool is_sync,
+    const SwapCompletionCallback& callback) const {
+  task_runner_->PostTask(
+      FROM_HERE, base::Bind(&DrmWindow::SchedulePageFlip, impl_, is_sync,
+                            CreateSafeCallback(callback)));
+  return true;
+}
+
+bool DrmWindowProxy::IsDisplayedOnUniversalDisplayLinkDevice() const {
+  bool is_udl = false;
+  PostSyncTask(

[spang, 2015/09/14 18:41:43]

What stops these sync queries from turning into races?

I think maybe we should do something like

initially, gpu main thread calls GetSurfaceConfiguration(window_id), and gets
back a struct

struct SurfaceConfiguration {
  scoped_refptr<DrmDevice> drm_device;
  bool requires_gl_finish; // is UDL
  gfx::Size size;
};

inside swap buffers, gpu main thread calls SchedulePageFlip(queued_planes,
surface_configuration);

On the DRM thread you can check that the configuration is unchanged and if not,
return NAK_RECREATE_BUFFERS.

[dnicoara, 2015/09/17 21:58:21]

I've re-done this function to no longer require a sync post.

As for your other concerns:
1) If surface resizes, this is already handled since we ignore requests when the
primary buffer is of the wrong size. We can also get this signal from the
buffers send with the ShedulePageFlip() call if we need to do anything fancy.

2) If the surface changes devices, we can also tell from the buffers since we
can look-up the device they were allocated on.

+      task_runner_,
+      CreateWeakPtrCallback(&DrmWindow::IsDisplayedOnUniversalDisplayLinkDevice,
+                            impl_, &is_udl));
+  return is_udl;
+}
+
+gfx::Rect DrmWindowProxy::GetBounds() const {

[spang, 2015/09/14 18:41:43]

I don't think this function should exist here.

[dnicoara, 2015/09/17 21:58:21]

Removed, no longer necessary.

+  gfx::Rect bounds;
+  PostSyncTask(task_runner_,
+               CreateWeakPtrCallback(&DrmWindow::bounds, impl_, &bounds));
+  return bounds;
+}
+
+void DrmWindowProxy::GetVSyncParameters(
+    const gfx::VSyncProvider::UpdateVSyncCallback& callback) const {
+  task_runner_->PostTask(FROM_HERE,
+                         base::Bind(&DrmWindow::GetVSyncParameters, impl_,
+                                    CreateSafeCallback(callback)));
+}
+
+scoped_refptr<DrmDevice> DrmWindowProxy::GetDrmDevice() const {
+  scoped_refptr<DrmDevice> drm;
+  PostSyncTask(
+      task_runner_,
+      CreateWeakPtrCallback(&DrmWindow::GetAllocationDrmDevice, impl_, &drm));
+  return drm;
+}
+
+}  // namespace ui