ozone: Add OzoneSurface object that is owned by compositor, GLSurface

ui/gfx/ozone/surface_ozone.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_GFX_OZONE_EGL_SURFACE_OZONE_H_
+#define UI_GFX_OZONE_EGL_SURFACE_OZONE_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/gfx/gfx_export.h"
+
+class SkCanvas;
+
+namespace gfx {
+
+class Rect;
+class VSyncProvider;
+
+// The platform-specific part of a EGL or software surface.
+//
+// This class owns any bits that the ozone implementation needs freed when
+// the software output or EGL surface is destroyed.
+//
+// If you want to paint on a window with ozone, you need to create a
+// SurfaceOzone for that window.
+//
+// The platform can support software, EGL, or both for painting on the
+// window. It is not necessary to override any methods for modes the
+// platform doesn't support, as the base class will fails initialization

[rjkroege, 2014/03/24 16:07:04]

nit: "fails initialization" is weird grammar.

[spang, 2014/03/24 16:42:11]

Done.

+// for all modes.
+class GFX_EXPORT SurfaceOzone {
+ public:
+  SurfaceOzone();
+  virtual ~SurfaceOzone();
+
+  // Initialize the surface for output using EGL/GLES2. Returns true if
+  // initialization was successful.
+  virtual bool InitializeEGL();
+
+  // Returns the EGL native window for rendering onto this surface.
+  // can be used to to create a GLSurface. This method may only be called in
+  // a process that has a valid GL context.
+  virtual intptr_t /* EGLNativeWindowType */ GetEGLNativeWindow();
+
+  // Initialize canvas for software output. Returns true of initialization

[rjkroege, 2014/03/24 16:07:04]

s/of/if/

[spang, 2014/03/24 16:42:11]

Done.

+  // was successful.
+  virtual bool InitializeCanvas();
+
+  // Returns a SkCanvas for the backing buffers. Drawing to the canvas will draw

[rjkroege, 2014/03/24 16:07:04]

For better compatibility with Skia, the long term intent is that there will be a
1 SkCanvas per buffer instead of a single SkCanvas containing two SkBitmap
instances. At a minimum, this should be noted. Better perhaps would be to change
this API now to return two canvas instances. (Which at present we can hackily
make the same perhaps.)

[spang, 2014/03/24 16:42:11]

Agreed, let's break the API slightly more now to avoid breaking it again.

Looking into it.

[spang, 2014/03/26 19:02:10]

I've coordinated with dnicoara to update the API here so that it hopefully does
not need to change again soon.

You now must call GetCanvas() each frame.

+  // to the native surface. The canvas is intended for use when no EGL
+  // acceleration is possible. Its implementation is optional when an EGL
+  // backend is provided for rendering.
+  virtual SkCanvas* GetCanvas();
+
+  // Attempts to resize the canvas to match the viewport size. Returns true if
+  // resizing was successful, otherwise false (native hardware may only support
+  // a single fixed size). If successful, you must call GetCanvas() again.
+  virtual bool ResizeCanvas(const gfx::Rect& viewport_size);
+
+  // Swap buffers in the SkCanvas. This back buffer becomes the new front

[rjkroege, 2014/03/24 16:07:04]

This too needs to be adjusted to reflect the "two canvas" model.

[spang, 2014/03/26 19:02:10]

Done.

+  // buffer and is presented, and the front buffer becomes the back buffer
+  // for subsequent draw operations.
+  virtual bool SwapCanvas();

[rjkroege, 2014/03/24 16:07:04]

Ozone will need to intercept SwapBuffers from EGL land to inter-op with HWC
(i.e. calling set). This method seems inadequate. 

[spang, 2014/03/24 16:42:11]

We can add [On]SwapBuffersEGL(void *display, void *surface) after the next patch
and call it from GLSurfaceOzoneEGL. This would allow platforms to override [or
supplement] swap behavior.

[rjkroege, 2014/03/24 20:23:15]

that sounds reasonable.

+
+  // Returns a gfx::VsyncProvider for the provided AcceleratedWidget. Note
+  // that this may be called after we have entered the sandbox so if there are
+  // operations (e.g. opening a file descriptor providing vsync events) that
+  // must be done outside of the sandbox, they must have been completed
+  // in InitializeHardware. Returns an empty scoped_ptr on error.
+  virtual scoped_ptr<gfx::VSyncProvider> CreateVSyncProvider();
+};
+
+}  // namespace gfx
+
+#endif  // UI_GFX_OZONE_SURFACE_OZONE_H_