native_viewport support for ozone

ui/ozone/platform/drm/host/drm_display_host_manager.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 "ui/ozone/platform/drm/host/drm_display_host_manager.h"
 
 #include <fcntl.h>
 #include <xf86drm.h>
 
 #include "base/files/file_enumerator.h"
@@ skipping 205 matching lines @@
 
   relinquish_display_control_callback_ = callback;
   display_control_change_pending_ = true;
 
   if (!proxy_->RelinquishDisplayControl())
     OnRelinquishDisplayControl(false);
 }
 
 void DrmDisplayHostManager::UpdateDisplays(
     const GetDisplaysCallback& callback) {
+  DCHECK(get_displays_callback_.is_null());
   get_displays_callback_ = callback;
   if (!proxy_->RefreshNativeDisplays()) {
     get_displays_callback_.Reset();
     RunUpdateDisplaysCallback(callback);
   }
 }
 
 void DrmDisplayHostManager::OnDeviceEvent(const DeviceEvent& event) {
   if (event.device_type() != DeviceEvent::DISPLAY)
     return;
@@ skipping 65 matching lines @@
 }
 
 void DrmDisplayHostManager::OnRemoveGraphicsDevice(const base::FilePath& path) {
   proxy_->RemoveGraphicsDevice(path);
   NotifyDisplayDelegate();
   task_pending_ = false;
   ProcessEvent();
 }
 
 void DrmDisplayHostManager::OnChannelEstablished(int host_id) {
-  // If in the middle of a configuration, just respond with the old list of
-  // displays. This is fine, since after the DRM resources are initialized and
-  // IPC-ed to the GPU NotifyDisplayDelegate() is called to let the display
-  // delegate know that the display configuration changed and it needs to
-  // update it again.
-  if (!get_displays_callback_.is_null()) {
-    base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE,
-        base::Bind(&DrmDisplayHostManager::RunUpdateDisplaysCallback,
-                   weak_ptr_factory_.GetWeakPtr(), get_displays_callback_));
-    get_displays_callback_.Reset();
-  }
+  // If in the middle of a configuration - don't respond here.
+  // Chromium does so, but that causes a problem:
+  // NotifyDisplayDelegate, below, triggers a new update display request which
+  // is
+  // fulfilled by the results from the first request. That result is empty
+  // because
+  // we haven't added a drm device yet).
+  // The second update display request generates non empty results,
+  // but those won't be forwarded to the observer because there is no longer
+  // an outstanding request.
 
   // Signal that we're taking DRM master since we're going through the
   // initialization process again and we'll take all the available resources.
   if (!take_display_control_callback_.is_null())
     OnTakeDisplayControl(true);
 
   if (!relinquish_display_control_callback_.is_null())
     OnRelinquishDisplayControl(false);
 
   drm_devices_.clear();
@@ skipping 119 matching lines @@
 
   callback.Run(snapshots);
 }
 
 void DrmDisplayHostManager::NotifyDisplayDelegate() const {
   if (delegate_)
     delegate_->OnConfigurationChanged();
 }
 
 }  // namespace ui