Add JPEG decoder for VAAPI JPEG decode acceleration

content/common/gpu/media/vaapi_jpeg_decoder.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 CONTENT_COMMON_GPU_MEDIA_VAAPI_JPEG_DECODER_H_
+#define CONTENT_COMMON_GPU_MEDIA_VAAPI_JPEG_DECODER_H_
+
+#include "base/macros.h"
+#include "content/common/content_export.h"
+#include "content/common/gpu/media/vaapi_wrapper.h"
+
+namespace media {
+struct JpegParseResult;
+}  // namespace media
+
+namespace content {
+
+// A JPEG decoder that utilizes VA-API hardware video decode acceleration on
+// Intel systems. Provides functionality to allow plugging VAAPI HW
+// acceleration into the JpegDecodeAccelerator framework.
+//
+// Clients of this class are expected to manage VA surfaces created via
+// VaapiWrapper, parse JPEG picture via media::ParseJpegPicture, and then pass
+// them to this class.
+//
+// This class must be called on a single thread, and does nothing internally on
+// any other thread.

[wuchengli, 2015/01/21 13:19:58]

This can be removed. A static method doesn't have states and can be called by
two places at the same time. I don't think we need to emphasis a static method
does not use another thread. 

[kcwu, 2015/01/23 07:51:33]

Done.

+class CONTENT_EXPORT VaapiJpegDecoder {
+ public:
+  // Decode a JPEG picture. It will fill VA-API parameters and call
+  // corresponding VA-API methods according to parsed JPEG result
+  // |parse_result|. Decoded data will be outputted to the given |va_surface|.
+  // Return false on failure.
+  // |vaapi_wrapper| should be initialized in kDecode mode with
+  // VAProfileJPEGBaseline profile.
+  // |va_surface| should be created with size at least as the picture size.
+  static bool Decode(VaapiWrapper* vaapi_wrapper,
+                     const media::JpegParseResult& parse_result,
+                     VASurfaceID va_surface);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(VaapiJpegDecoder);

[wuchengli, 2015/01/21 13:19:58]

DISALLOW_IMPLICIT_CONSTRUCTORS. Let's also disallow the default constructor.

[kcwu, 2015/01/23 07:51:33]

Done.

+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_VAAPI_JPEG_DECODER_H_