Make Mac swap code like other platforms

gpu/ipc/client/gpu_process_hosted_ca_layer_tree_params.h

+// Copyright 2016 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 <IOSurface/IOSurface.h>
+
+#include "base/mac/scoped_cftyperef.h"
+#include "gpu/gpu_export.h"
+#include "ui/base/cocoa/remote_layer_api.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace gpu {
+
+struct GPU_EXPORT GpuProcessHostedCALayerTreeParamsMac {
+  GpuProcessHostedCALayerTreeParamsMac();
+  ~GpuProcessHostedCALayerTreeParamsMac();
+
+  int surface_handle = 0;
+  CAContextID ca_context_id = 0;
+  bool fullscreen_low_power_ca_context_valid = false;
+  CAContextID fullscreen_low_power_ca_context_id = 0;
+  base::ScopedCFTypeRef<IOSurfaceRef> io_surface;

[piman, 2016/05/09 16:23:59]

FYI, just a thought, don't worry about it since it sounds all this is somewhat
temporary, but you could define a
IPC::ParamTraits<base::ScopedCFTypeRef<IOSurfaceRef>> which does the mac port
creation/lookup, and then it would be trivial to pass the
GpuProcessHostedCALayerTreeParamsMac directly in the
GpuCommandBufferMsg_SwapBuffersCompleted_Params.

[ccameron, 2016/05/09 18:40:36]

That's an interesting idea -- I'll keep that in mind.

+  gfx::Size pixel_size;
+  float scale_factor = 1;
+};
+
+}  // namespace gpu
+