Fix black screen when switching primary display without bounds change

ui/ozone/platform/drm/gpu/drm_buffer.h

 // 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.
 
 #ifndef UI_OZONE_PLATFORM_DRM_GPU_DRM_BUFFER_H_
 #define UI_OZONE_PLATFORM_DRM_GPU_DRM_BUFFER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 22 matching lines @@
   // used for modesetting.
   bool Initialize(const SkImageInfo& info, bool should_register_framebuffer);
 
   SkCanvas* GetCanvas() const;
 
   // ScanoutBuffer:
   uint32_t GetFramebufferId() const override;
   uint32_t GetFramebufferPixelFormat() const override;
   uint32_t GetHandle() const override;
   gfx::Size GetSize() const override;
+  const DrmDevice* GetDrmDevice() const override;
   bool RequiresGlFinish() const override;
 
  protected:
   ~DrmBuffer() override;
 
   scoped_refptr<DrmDevice> drm_;
 
   // Length of a row of pixels.
   uint32_t stride_ = 0;
 
@@ skipping 15 matching lines @@
 
   // Wrapper around the native pixel memory.
   sk_sp<SkSurface> surface_;
 
   DISALLOW_COPY_AND_ASSIGN(DrmBuffer);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRM_GPU_DRM_BUFFER_H_