drm: GPU process manages VGEM fd.

ui/ozone/platform/drm/gpu/drm_gpu_display_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/gpu/drm_gpu_display_manager.h"
 
 #include "ui/display/types/gamma_ramp_rgb_entry.h"
 #include "ui/ozone/common/display_util.h"
 #include "ui/ozone/platform/drm/common/drm_util.h"
 #include "ui/ozone/platform/drm/gpu/drm_device.h"
@@ skipping 51 matching lines @@
     : screen_manager_(screen_manager), drm_device_manager_(drm_device_manager) {
 }
 
 DrmGpuDisplayManager::~DrmGpuDisplayManager() {
 }
 
 std::vector<DisplaySnapshot_Params> DrmGpuDisplayManager::GetDisplays() {
   ScopedVector<DrmDisplay> old_displays(displays_.Pass());
   std::vector<DisplaySnapshot_Params> params_list;
 
-  const DrmDeviceVector& devices = drm_device_manager_->GetDrmDevices();
+  DrmDeviceVector devices = drm_device_manager_->GetDrmDevices();
   // Unique identifier used to create the display id.
   size_t index = 0;
   for (const auto& drm : devices) {
     ScopedVector<HardwareDisplayControllerInfo> display_infos =
         GetAvailableDisplayControllerInfos(drm->get_fd());
     for (auto* display_info : display_infos) {
       auto it = std::find_if(
           old_displays.begin(), old_displays.end(),
           DisplayComparator(drm, display_info->crtc()->crtc_id,
                             display_info->connector()->connector_id));
       if (it != old_displays.end()) {
         displays_.push_back(*it);
         old_displays.weak_erase(it);
       } else {
         displays_.push_back(new DrmDisplay(screen_manager_, drm));
       }
 
       params_list.push_back(displays_.back()->Update(display_info, index++));
     }
   }
 
   NotifyScreenManager(displays_.get(), old_displays.get());
   return params_list;
 }
 
 bool DrmGpuDisplayManager::TakeDisplayControl() {
-  const DrmDeviceVector& devices = drm_device_manager_->GetDrmDevices();
+  DrmDeviceVector devices = drm_device_manager_->GetDrmDevices();
   for (const auto& drm : devices) {
     if (!drm->SetMaster()) {
       LOG(ERROR) << "Failed to take control of the display";
       return false;
     }
   }
 
   return true;
 }
 
 bool DrmGpuDisplayManager::RelinquishDisplayControl() {
-  const DrmDeviceVector& devices = drm_device_manager_->GetDrmDevices();
+  DrmDeviceVector devices = drm_device_manager_->GetDrmDevices();
   for (const auto& drm : devices) {
     if (!drm->DropMaster()) {
       LOG(ERROR) << "Failed to relinquish control of the display";
       return false;
     }
   }
 
   return true;
 }
 
@@ skipping 102 matching lines @@
 
     if (it == old_displays.end()) {
       screen_manager_->AddDisplayController(new_displays[i]->drm(),
                                             new_displays[i]->crtc(),
                                             new_displays[i]->connector());
     }
   }
 }
 
 }  // namespace ui