ozone: Introduce ClientPixmap and ClientPixmapFactory for non-GPU processes.

ui/ozone/public/native_pixmap_manager.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.
+
+#ifndef UI_OZONE_PUBLIC_NATIVE_PIXMAP_MANAGER_H_
+#define UI_OZONE_PUBLIC_NATIVE_PIXMAP_MANAGER_H_
+
+#include <vector>
+
+#include "ui/ozone/ozone_export.h"
+#include "ui/ozone/public/surface_factory_ozone.h"
+
+namespace ui {
+
+// The Ozone interface allows external implementations to hook into Chromium to
+// provide a native pixmap for Browser and Render process.

[reveman, 2015/07/23 18:25:23]

This doesn't match the interface. All this interface currently does is provide a
function that allows us to query supported configurations. What's missing?

Also, Browser/Render process are content/ concepts that this code is not
supposed to be aware of. Can you explain what this interface provides without
using those terms?

[dshwang, 2015/07/24 12:19:00]

Future CL will add "scoped_refptr<NativePixmap> CreateFromFileDescriptor()"
method;
https://codereview.chromium.org/1134993003/diff/200001/ui/ozone/public/native...
The CreateFromFileDescriptor() method is main motivation of this class.
s/Browser and Render process/non-GPU processes/

ozone is aware of gpu process;
https://code.google.com/p/chromium/codesearch#chromium/src/ui/ozone/public/gp...
It's because ozone is gpu process backend.

[reveman, 2015/07/24 14:54:07]

Please include all functions (with NOTIMPLEMENTED statements if necessary) in
this interface as that makes it easier to understand what it's used for.
Otherwise we have a description that doesn't match the code.

Note: I'd really like to see both a CreateNativePixmapFromFileDescriptor() and
CreateNativePixmap() function as part of this interface so it can replace the
current ui::GpuMemoryBufferFactoryOzoneNativeBuffer code.

[dshwang, 2015/07/24 18:20:18]

Ok, I'll do it in next patch.
As I explained above, CreateNativePixmap() function should not be part of this
interface because NativePixmapManager should not know real GPU device.

+class OZONE_EXPORT NativePixmapManager {
+ public:
+  static NativePixmapManager* GetInstance();
+  static void SetInstance(NativePixmapManager* instance);
+
+  static scoped_ptr<NativePixmapManager> Create();
+
+  virtual ~NativePixmapManager();
+
+  struct Configuration {
+    SurfaceFactoryOzone::BufferFormat format;
+    SurfaceFactoryOzone::BufferUsage usage;
+  };
+
+  // Gets supported format/usage configurations.
+  virtual std::vector<Configuration> GetSupportedNativePixmapConfigurations()
+      const = 0;
+
+ protected:
+  NativePixmapManager();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(NativePixmapManager);
+};
+
+}  // namespace ui
+
+#endif  // UI_OZONE_PUBLIC_NATIVE_PIXMAP_MANAGER_H_