ozone: Implement zero/one-copy texture for Ozone GBM.

ui/ozone/platform/drm/gpu/gbm_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_GBM_BUFFER_H_
 #define UI_OZONE_PLATFORM_DRM_GPU_GBM_BUFFER_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/gfx/geometry/size.h"
@@ skipping 24 matching lines @@
 
 class GbmPixmap : public NativePixmap {
  public:
   GbmPixmap(const scoped_refptr<GbmBuffer>& buffer);
   bool Initialize();
 
   // NativePixmap:
   void* GetEGLClientBuffer() override;
   int GetDmaBufFd() override;
   int GetDmaBufPitch() override;
+  BufferUsage GetBufferUsage() const override;
+  void* Map() override;
+  void Unmap() override;
 
   scoped_refptr<GbmBuffer> buffer() { return buffer_; }
 
  private:
   ~GbmPixmap() override;
 
   scoped_refptr<GbmBuffer> buffer_;
   int dma_buf_ = -1;
 
   DISALLOW_COPY_AND_ASSIGN(GbmPixmap);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRM_GPU_GBM_BUFFER_H_