gfx: introduce GpuMemoryBufferAttrib to communicate format modifiers

ui/gfx/buffer_types.h

 // Copyright 2015 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 <stdint.h>
+#include <vector>
 
 #ifndef UI_GFX_BUFFER_TYPES_H_
 #define UI_GFX_BUFFER_TYPES_H_
 
 namespace gfx {
 
 // The format needs to be taken into account when mapping a buffer into the
 // client's address space.
 enum class BufferFormat {
   ATC,
@@ skipping 29 matching lines @@
   SCANOUT,
   SCANOUT_CPU_READ_WRITE,
   GPU_READ_CPU_READ_WRITE,
   // TODO(reveman): Merge this with GPU_READ_CPU_READ_WRITE when SurfaceTexture
   // backed buffers are single buffered and support it.
   GPU_READ_CPU_READ_WRITE_PERSISTENT,
 
   LAST = GPU_READ_CPU_READ_WRITE_PERSISTENT
 };
 
+struct GpuMemoryBufferAttrib {
+  GpuMemoryBufferAttrib(BufferFormat format, uint64_t modifier)
+      : format(format), modifier(modifier){};
+  GpuMemoryBufferAttrib(){};
+  ~GpuMemoryBufferAttrib(){};
+
+  bool operator<(GpuMemoryBufferAttrib const& rhs) const {
+    if (format == rhs.format)
+      return modifier < rhs.modifier;
+    else
+      return format < rhs.format;
+  }
+
+  BufferFormat format;
+  uint64_t modifier;
+};
+
+using GpuMemoryBufferAttribVector = std::vector<GpuMemoryBufferAttrib>;
+
 }  // namespace gfx
 
 #endif  // UI_GFX_BUFFER_TYPES_H_