ozone: Directly provide size of active mode from HardwareDisplayController

ui/ozone/platform/dri/dri_surface.cc

Index: ui/ozone/platform/dri/dri_surface.cc
diff --git a/ui/ozone/platform/dri/dri_surface.cc b/ui/ozone/platform/dri/dri_surface.cc
index f12ef693570dce96e6cc379473aa5079e170d886..dc166fdbf0276b359a7989189d16e00cc6b6e153 100644
--- a/ui/ozone/platform/dri/dri_surface.cc
+++ b/ui/ozone/platform/dri/dri_surface.cc
@@ -58,10 +58,8 @@ void DriSurface::ResizeCanvas(const gfx::Size& viewport_size) {
 
   // For the display buffers use the mode size since a |viewport_size| smaller
   // than the display size will not scanout.
-  gfx::Size mode_size(controller->get_mode().hdisplay,
-                      controller->get_mode().vdisplay);
   for (size_t i = 0; i < arraysize(buffers_); ++i)
-    buffers_[i] = AllocateBuffer(dri_, mode_size);
+    buffers_[i] = AllocateBuffer(dri_, controller->GetModeSize());
 }
 
 void DriSurface::PresentCanvas(const gfx::Rect& damage) {