[1.5/2][Ozone-Drm] Keep track of display origin

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 66 matching lines @@
   ScopedVector<DrmDisplay> old_displays(displays_.Pass());
   std::vector<DisplaySnapshot_Params> params_list;
 
   const 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) {
-      DisplaySnapshot_Params params =
-          CreateDisplaySnapshotParams(display_info, drm->get_fd(), index++);
+      auto it = std::find_if(
+          old_displays.begin(), old_displays.end(),

[spang, 2015/05/13 19:01:20]

I'm not a fan of this.

Can you update displays_ first, then convert displays_ to
std::vector<DisplaySnapshot_Params>()?

[dnicoara, 2015/05/13 19:10:36]

Hmm, it is simpler to create the std::vector<DisplaySnapshot_Params>, then
update displays_ since the display ID is needed from DisplaySnapshot_Params. I
don't think this has a huge mental overhead given that the important operations
are just push_back(). Though I'm happy to change if you think that's cleaner :)

+          DisplayComparator(drm, display_info->crtc()->crtc_id,
+                            display_info->connector()->connector_id));
+      gfx::Point origin;
+      // Because each display has its own surface, display layout isn't tracked
+      // at the DRM level. We must keep track of the display origins otherwise
+      // we'll lose the layout information.
+      if (it != old_displays.end())
+        origin = (*it)->origin();
+
+      DisplaySnapshot_Params params = CreateDisplaySnapshotParams(
+          display_info, drm->get_fd(), index++, origin);
       params_list.push_back(params);
 
       displays_.push_back(
           new DrmDisplay(screen_manager_, params.display_id, drm,
                          display_info->crtc()->crtc_id,
                          display_info->connector()->connector_id,
-                         GetDrmModeVector(display_info->connector())));
+                         GetDrmModeVector(display_info->connector()), origin));
     }
   }
 
   NotifyScreenManager(displays_.get(), old_displays.get());
   return params_list;
 }
 
 bool DrmGpuDisplayManager::TakeDisplayControl() {
   const DrmDeviceVector& devices = drm_device_manager_->GetDrmDevices();
   for (const auto& drm : devices) {
@@ skipping 123 matching lines @@
 
     if (it == old_displays.end()) {
       screen_manager_->AddDisplayController(new_displays[i]->drm(),
                                             new_displays[i]->crtc(),
                                             new_displays[i]->connector());
     }
   }
 }
 
 }  // namespace ui