gfx: introduce GpuMemoryBufferAttrib to communicate format modifiers

ui/gfx/mojo/buffer_types_struct_traits.cc

Index: ui/gfx/mojo/buffer_types_struct_traits.cc
diff --git a/ui/gfx/mojo/buffer_types_struct_traits.cc b/ui/gfx/mojo/buffer_types_struct_traits.cc
index 52be89b5a1e3b1fb6a4b299b78596e98a502aa32..1e7896fa48662a9801443f61ef5f8f7a54ccb93a 100644
--- a/ui/gfx/mojo/buffer_types_struct_traits.cc
+++ b/ui/gfx/mojo/buffer_types_struct_traits.cc
@@ -60,6 +60,20 @@ bool StructTraits<
 #endif
 }
 
+bool StructTraits<gfx::mojom::GpuMemoryBufferAttribDataView,
+                  gfx::GpuMemoryBufferAttrib>::
+    Read(gfx::mojom::GpuMemoryBufferAttribDataView attrib,
+         gfx::GpuMemoryBufferAttrib* out) {
+#if defined(OS_LINUX)
+  EnumTraits<gfx::mojom::BufferFormat, gfx::BufferFormat>::FromMojom(
+      attrib.format(), &out->format);
+  out->modifier = attrib.modifier();
+  return true;
+#else
+  return false;
+#endif
+}
+
 mojo::ScopedHandle StructTraits<gfx::mojom::GpuMemoryBufferHandleDataView,
                                 gfx::GpuMemoryBufferHandle>::
     shared_memory_handle(const gfx::GpuMemoryBufferHandle& handle) {