[Mojo Video Capture] Add test coverage for accelerated jpeg decoding

media/gpu/fake_jpeg_decode_accelerator.cc

+// Copyright 2017 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.
+
+#include "media/gpu/fake_jpeg_decode_accelerator.h"
+
+#include "base/bind.h"
+#include "base/single_thread_task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "media/gpu/shared_memory_region.h"
+
+namespace media {
+
+FakeJpegDecodeAccelerator::FakeJpegDecodeAccelerator(
+    const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner)
+    : client_task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      io_task_runner_(std::move(io_task_runner)),
+      decoder_thread_("FakeJpegDecoderThread"),
+      weak_factory_(this) {}
+
+FakeJpegDecodeAccelerator::~FakeJpegDecodeAccelerator() {
+  DCHECK(client_task_runner_->BelongsToCurrentThread());
+}
+
+bool FakeJpegDecodeAccelerator::Initialize(
+    JpegDecodeAccelerator::Client* client) {
+  DCHECK(client_task_runner_->BelongsToCurrentThread());
+  client_ = client;
+
+  if (!decoder_thread_.Start()) {
+    DLOG(ERROR) << "Failed to start decoding thread.";
+    return false;
+  }
+  decoder_task_runner_ = decoder_thread_.task_runner();
+
+  return true;
+}
+
+void FakeJpegDecodeAccelerator::Decode(
+    const BitstreamBuffer& bitstream_buffer,
+    const scoped_refptr<VideoFrame>& video_frame) {
+  DCHECK(io_task_runner_->BelongsToCurrentThread());
+
+  // SharedMemoryRegion will take over the |bitstream_buffer.handle()|.
+  std::unique_ptr<SharedMemoryRegion> src_shm(
+      new SharedMemoryRegion(bitstream_buffer, true));
+  if (!src_shm->Map()) {
+    DLOG(ERROR) << "Unable to map shared memory in FakeJpegDecodeAccelerator";
+    NotifyError(bitstream_buffer.id(), JpegDecodeAccelerator::UNREADABLE_INPUT);
+    return;
+  }
+
+  // Unretained |this| is safe because |this| owns |decoder_thread_|.
+  decoder_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&FakeJpegDecodeAccelerator::DecodeOnDecoderThread,
+                            base::Unretained(this), bitstream_buffer,
+                            video_frame, base::Passed(&src_shm)));
+}
+
+void FakeJpegDecodeAccelerator::DecodeOnDecoderThread(
+    const BitstreamBuffer& bitstream_buffer,
+    const scoped_refptr<VideoFrame>& video_frame,
+    std::unique_ptr<SharedMemoryRegion> src_shm) {
+  DCHECK(decoder_task_runner_->BelongsToCurrentThread());
+
+  // Do not actually decode the Jpeg data.
+  // Instead, just fill the output buffer with zeros.
+  size_t allocation_size =
+      VideoFrame::AllocationSize(PIXEL_FORMAT_I420, video_frame->coded_size());
+  memset(video_frame->data(0), 0, allocation_size);
+
+  client_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&FakeJpegDecodeAccelerator::OnDecodeDoneOnClientThread,
+                 weak_factory_.GetWeakPtr(), bitstream_buffer.id()));
+}
+
+bool FakeJpegDecodeAccelerator::IsSupported() {
+  return true;
+}
+
+void FakeJpegDecodeAccelerator::NotifyError(int32_t bitstream_buffer_id,
+                                            Error error) {
+  client_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&FakeJpegDecodeAccelerator::NotifyErrorOnClientThread,
+                 weak_factory_.GetWeakPtr(), bitstream_buffer_id, error));
+}
+
+void FakeJpegDecodeAccelerator::NotifyErrorOnClientThread(
+    int32_t bitstream_buffer_id,
+    Error error) {
+  DCHECK(client_task_runner_->BelongsToCurrentThread());
+  client_->NotifyError(bitstream_buffer_id, error);
+}
+
+void FakeJpegDecodeAccelerator::OnDecodeDoneOnClientThread(
+    int32_t input_buffer_id) {
+  DCHECK(client_task_runner_->BelongsToCurrentThread());
+  client_->VideoFrameReady(input_buffer_id);
+}
+
+}  // namespace media