Force buffer re-allocation when the backing display changes

ui/ozone/platform/drm/gpu/drm_window.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_window.h"
 
 #include "base/trace_event/trace_event.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkDevice.h"
 #include "third_party/skia/include/core/SkSurface.h"
@@ skipping 108 matching lines @@
   if (controller_)
     controller_->MoveCursor(location);
 }
 
 void DrmWindow::QueueOverlayPlane(const OverlayPlane& plane) {
   pending_planes_.push_back(plane);
 }
 
 bool DrmWindow::SchedulePageFlip(bool is_sync,
                                  const SwapCompletionCallback& callback) {
+  if (force_buffer_reallocation_) {
+    // Clear pending planes otherwise the next call to queue planes will just
+    // add on top.
+    pending_planes_.clear();
+    force_buffer_reallocation_ = false;
+    callback.Run(gfx::SwapResult::SWAP_NAK_RECREATE_BUFFERS);
+    return true;
+  }
+
   last_submitted_planes_.clear();
   last_submitted_planes_.swap(pending_planes_);
   last_swap_sync_ = is_sync;
 
   if (controller_) {
     return controller_->SchedulePageFlip(last_submitted_planes_, is_sync, false,
                                          callback);
   }
 
   callback.Run(gfx::SwapResult::SWAP_ACK);
@@ skipping 58 matching lines @@
   cursor_frame_++;
   cursor_frame_ %= cursor_bitmaps_.size();
 
   ResetCursor(true);
 }
 
 void DrmWindow::SetController(HardwareDisplayController* controller) {
   if (controller_ == controller)
     return;
 
+  // Force buffer reallocation since the window moved to a different controller.
+  // This is required otherwise the GPU will eventually try to render into the
+  // buffer currently showing on the old controller (there is no guarantee that
+  // the old controller has been updated in the meantime).
+  force_buffer_reallocation_ = true;
+
   controller_ = controller;
   device_manager_->UpdateDrmDevice(
       widget_, controller ? controller->GetAllocationDrmDevice() : nullptr);
 
   UpdateCursorBuffers();
   // We changed displays, so we want to update the cursor as well.
   ResetCursor(false /* bitmap_only */);
 }
 
 void DrmWindow::UpdateCursorBuffers() {
@@ skipping 18 matching lines @@
       if (!cursor_buffers_[i]->Initialize(
               info, false /* should_register_framebuffer */)) {
         LOG(FATAL) << "Failed to initialize cursor buffer";
         return;
       }
     }
   }
 }
 
 }  // namespace ui