android_webview: changes to support Android GraphicBuffers

ui/gl/gpu_memory_buffer.h

+// Copyright 2013 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_GPU_MEMORY_BUFFER_H_
+#define UI_GL_GPU_MEMORY_BUFFER_H_
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace gfx {
+class Size;
+
+// Interface for creating and accessing a zero-copy GPU memory buffer.
+// This design evolved from the generalization of GraphicBuffer API
+// of Android framework.
+//
+// THREADING CONSIDERATIONS:
+//
+// This interface is thread-safe. However, multiple threads calling
+// MapForWrite() simultaneously may result in undefined behavior
+// and is not allowed.
+class GpuMemoryBuffer {
+ public:
+  typedef base::Callback<scoped_ptr<gfx::GpuMemoryBuffer>(gfx::Size)> Create;
+
+  // Frees a previously allocated buffer. Freeing a buffer that is still
+  // mapped in any process is undefined behavior.
+  virtual ~GpuMemoryBuffer() {}
+
+  // Maps the buffer so the client can write the bitmap data in |*vaddr|
+  // subsequently. This call may block, for instance if the hardware needs
+  // to finish rendering or if CPU caches need to be synchronized.
+  virtual void MapForWrite(void** vaddr) = 0;
+
+  // Unmaps the buffer. Called after all changes to the buffer are
+  // completed.
+  virtual void Unmap() = 0;
+
+  // Returns the native pointer for the buffer.
+  virtual void* GetNativeBuffer() = 0;
+
+  // Returns the stride in pixels for the buffer.
+  virtual uint32 GetStride() = 0;
+};
+
+}  // namespace gfx
+
+#endif  // UI_GL_GPU_MEMORY_BUFFER_H_