gpu: Add async pixel transfer interface, stub and tests.

ui/gl/async_pixel_transfer_delegate.h

Index: ui/gl/async_pixel_transfer_delegate.h
diff --git a/ui/gl/async_pixel_transfer_delegate.h b/ui/gl/async_pixel_transfer_delegate.h
new file mode 100644
index 0000000000000000000000000000000000000000..f1946bb35499608c189c8a26e9594a9509926372
--- /dev/null
+++ b/ui/gl/async_pixel_transfer_delegate.h
@@ -0,0 +1,59 @@
+// Copyright (c) 2011 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_GL_ASYNC_TASK_DELEGATE_H_

[apatrick, 2012/12/03 21:23:59]

At first I was like, this definitely shouldn't be in this directory. I'm not
sure now. It doesn't have any dependencies on gpu/, which is great. I don't
think it needs a new target. I will ponder.

[epennerAtGoogle, 2012/12/03 22:48:45]

I initially had this code in gpu/ but ran into problems with #including EGL
headers. This file needs the android specific headers and something is different
about this build target. I can dig into it if there is a better location to put
this.

+#define UI_GL_ASYNC_TASK_DELEGATE_H_
+
+#include "base/basictypes.h"
+
+namespace gfx {
+
+// AsyncPixelTransferState holds the resources required to do async
+// transfers on one texture. It should stay alive for the lifetime
+// of the texture to allow multiple transfers.
+class AsyncPixelTransferState

[greggman, 2012/12/05 02:23:42]

I'm just guessing that in order for this to work in the shared library build
this is going to have to be

class GL_EXPORT AsyncPixelTransfrerState, similarly for the class below and
include "ui/gl/gl_export.h"

[epenner, 2012/12/08 03:15:03]

Done.

+    : public base::RefCounted<AsyncPixelTransferState> {

[apatrick, 2012/12/03 21:23:59]

RefCountedThreadSafe will do atomic increment / decrement for ref counting and I
think you might want that.

[epennerAtGoogle, 2012/12/03 22:48:45]

Currently lifetime for this object is controlled entirely on the main thread. In
one case a reply holds a reference to insure it isn't deleted before a task is
complete, but since the reply executes on the main thread I think it's safe.

+ public:
+  AsyncPixelTransferState() {}
+  virtual ~AsyncPixelTransferState() {};
+ private:

[greggman, 2012/12/05 02:23:42]

nit: one empty line before private

[epenner, 2012/12/08 03:15:03]

Done.

+  DISALLOW_COPY_AND_ASSIGN(AsyncPixelTransferState);
+};
+
+
+class AsyncPixelTransferDelegate {
+ public:
+  // TODO: Should this be owned by a GPU process object?
+  // We only need one in the GPU process, so this is currently
+  // just a lazy instance.
+  static AsyncPixelTransferDelegate* Get();
+
+  virtual scoped_refptr<AsyncPixelTransferState>
+      CreatePixelTransferState(GLuint texture) = 0;
+
+  virtual void AsyncNotifyCompletion(
+      const base::Closure& task) = 0;
+
+  virtual void AsyncTexSubImage2D(
+      AsyncPixelTransferState*,
+      GLenum target,
+      GLint level,
+      GLint xoffset,
+      GLint yoffset,
+      GLsizei width,
+      GLsizei height,
+      GLenum format,
+      GLenum type,
+      const void* data) = 0;
+
+ protected:
+  AsyncPixelTransferDelegate() {}
+  virtual ~AsyncPixelTransferDelegate() {}
+ private:

[greggman, 2012/12/05 02:23:42]

nit: one empty line before private

[epenner, 2012/12/08 03:15:03]

Done.

+  DISALLOW_COPY_AND_ASSIGN(AsyncPixelTransferDelegate);
+};
+
+}  // namespace gfx
+
+#endif  // UI_GL_ASYNC_TASK_DELEGATE_H_