[Ozone-DRI] Reuse framebuffer when re-enabling CRTC

ui/ozone/platform/dri/hardware_display_controller.cc

Index: ui/ozone/platform/dri/hardware_display_controller.cc
diff --git a/ui/ozone/platform/dri/hardware_display_controller.cc b/ui/ozone/platform/dri/hardware_display_controller.cc
index 92e84a2a772f889aad75322ebcef1ab4d0c134e8..7ec4f0dcbc95c4e1f5cc0b4e7883a3fffd9b2db1 100644
--- a/ui/ozone/platform/dri/hardware_display_controller.cc
+++ b/ui/ozone/platform/dri/hardware_display_controller.cc
@@ -48,6 +48,7 @@ void HandlePageFlipEvent(int fd,
 HardwareDisplayController::HardwareDisplayController(
     scoped_ptr<CrtcController> controller)
     : is_disabled_(true) {
+  memset(&mode_, 0, sizeof(mode_));
   AddCrtc(controller.Pass());
 }
 
@@ -75,12 +76,8 @@ bool HardwareDisplayController::Enable() {
   TRACE_EVENT0("dri", "HDC::Enable");
   DCHECK(!current_planes_.empty());
   const OverlayPlane* primary = OverlayPlane::GetPrimaryPlane(current_planes_);
-  DCHECK(primary->buffer.get());
-  bool status = true;
-  for (size_t i = 0; i < crtc_controllers_.size(); ++i)
-    status &= crtc_controllers_[i]->Modeset(*primary, mode_);
 
-  return status;
+  return Modeset(*primary, mode_);
 }
 
 void HardwareDisplayController::Disable() {