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

ui/gl/async_pixel_transfer_delegate.h

+// 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_
+#define UI_GL_ASYNC_TASK_DELEGATE_H_
+
+#include "base/basictypes.h"
+#include "build/build_config.h"
+#include "ui/gl/gl_bindings.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
+    : public base::RefCounted<AsyncPixelTransferState> {

[apatrick_chromium, 2012/12/04 20:59:22]

RefCountedThreadSafe

[epenner, 2012/12/08 03:15:04]

I haven't made this thread safe as the lifetime is currently controlled entirely
on the main thread. For tasks, only the reply has a reference, so the deref
happens back on the main thread after the task is complete.

+ public:
+  AsyncPixelTransferState() {}
+  virtual ~AsyncPixelTransferState() {};
+
+  // Returns true if there is a transfer in progress.
+  virtual bool TransferIsInProgress() = 0;
+
+  // Bind the async texture and perform any other custom binding.
+  // TODO(epenner): Android currently needs this to lazily bind
+  // a new EGLImage to the texture. We can get rid of this
+  // if we can make the textures context current during a
+  // 'completed' callback on the main thread.
+  virtual void BindTexture(GLenum target) = 0;
+
+ private:
+  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& notify_task) = 0;
+
+  virtual void AsyncTexImage2D(
+    AsyncPixelTransferState*,

[apatrick_chromium, 2012/12/04 20:59:22]

nit: indentation is out by 2 spaces

[epenner, 2012/12/08 03:15:04]

Done.

+    GLenum target,
+    GLint level,
+    GLenum internal_format,
+    GLsizei width,
+    GLsizei height,
+    GLint border,
+    GLenum format,
+    GLenum type,
+    const void* data) = 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:
+  DISALLOW_COPY_AND_ASSIGN(AsyncPixelTransferDelegate);
+};
+
+}  // namespace gfx
+
+#endif  // UI_GL_ASYNC_TASK_DELEGATE_H_