[Ozone-DRM] Simplify CrtcController::SignalPageFlipRequest

ui/ozone/platform/drm/gpu/crtc_controller.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/crtc_controller.h"
 
 #include "base/logging.h"
 #include "base/time/time.h"
 #include "ui/ozone/platform/drm/gpu/drm_device.h"
 #include "ui/ozone/platform/drm/gpu/page_flip_request.h"
@@ skipping 14 matching lines @@
         drm_->plane_manager()->planes();
     for (auto* plane : all_planes) {
       if (plane->owning_crtc() == crtc_) {
         plane->set_owning_crtc(0);
         plane->set_in_use(false);
       }
     }
 
     SetCursor(nullptr);
     drm_->DisableCrtc(crtc_);
-    SignalPageFlipRequest();
+    if (page_flip_request_)
+      SignalPageFlipRequest();
   }
 }
 
 bool CrtcController::Modeset(const OverlayPlane& plane, drmModeModeInfo mode) {
   if (!drm_->SetCrtc(crtc_, plane.buffer->GetFramebufferId(),
                      std::vector<uint32_t>(1, connector_), &mode)) {
     PLOG(ERROR) << "Failed to modeset: crtc=" << crtc_
                 << " connector=" << connector_
                 << " framebuffer_id=" << plane.buffer->GetFramebufferId()
                 << " mode=" << mode.hdisplay << "x" << mode.vdisplay << "@"
@@ skipping 115 matching lines @@
   if (!status) {
     PLOG(ERROR) << "drmModeSetCursor: device " << drm_->device_path().value()
                 << " crtc " << crtc_ << " handle " << handle << " size "
                 << size.ToString();
   }
 
   return status;
 }
 
 void CrtcController::SignalPageFlipRequest() {
-  if (page_flip_request_.get()) {
-    // If another frame is queued up and available immediately, calling Signal()
-    // may result in a call to SchedulePageFlip(), which will override
-    // page_flip_request_ and possibly release the ref. Stash previous request
-    // locally to  avoid deleting the object we are making a call on.
-    scoped_refptr<PageFlipRequest> last_request;
-    last_request.swap(page_flip_request_);
-    last_request->Signal(gfx::SwapResult::SWAP_ACK);
-  }
+  scoped_refptr<PageFlipRequest> request;
+  request.swap(page_flip_request_);
+  request->Signal(gfx::SwapResult::SWAP_ACK);
 }
 
 }  // namespace ui