Implemented software output device for Aura.

content/renderer/gpu/compositor_software_output_device.h

+// Copyright (c) 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 CONTENT_RENDERER_GPU_COMPOSITOR_SOFTWARE_OUTPUT_DEVICE_H_
+#define CONTENT_RENDERER_GPU_COMPOSITOR_SOFTWARE_OUTPUT_DEVICE_H_
+
+#include "base/memory/scoped_ptr.h"

[piman, 2013/03/27 21:49:28]

I don't think you need this.

+#include "base/memory/scoped_vector.h"
+#include "base/threading/non_thread_safe.h"
+#include "cc/output/software_output_device.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/surface/transport_dib.h"
+
+namespace content {
+
+// This class can be created only on the main thread, but then becomes pinned
+// to a fixed thread when bindToClient is called.

[piman, 2013/03/27 21:49:28]

nit: BindToClient

+class CompositorSoftwareOutputDevice

[piman, 2013/03/27 21:49:28]

I don't see this class instantiated anywhere yet.

+    : NON_EXPORTED_BASE(public cc::SoftwareOutputDevice),
+      NON_EXPORTED_BASE(public base::NonThreadSafe) {

[piman, 2013/03/27 21:49:28]

If the above comment is true, you should see asserts in the destructor since you
don't DetachFromThread. Also, NonThreadSafe doesn't give you a lot of guarantees
if you don't check CalledOnValidThread()

I think you want to call DetachFromThread in the constructor, and then
DCHECK(CalledOnValidThread()) in each method.

+public:
+  CompositorSoftwareOutputDevice();
+  virtual ~CompositorSoftwareOutputDevice();
+
+  virtual void Resize(gfx::Size size) OVERRIDE;
+
+  virtual SkCanvas* BeginPaint(gfx::Rect damage_rect) OVERRIDE;
+  virtual void EndPaint(cc::SoftwareFrameData* frame_data) OVERRIDE;
+
+  virtual void ReclaimDIB(TransportDIB::Handle handle) OVERRIDE;
+
+private:
+  size_t ViewportSizeInBytes() const {
+    return 4 * viewport_size_.GetArea();
+  }
+
+  TransportDIB* CreateDIB() {

[piman, 2013/03/27 21:49:28]

This method is non-trivial, move to the .cc file? There's no advantage to
putting it in the header since no outside class has an opportunity to inline
this.

Without it, you should even be able to remove the ui/surface/transport_dib.h
header, just forward-declare (and only include in the .cc file).

+    TransportDIB* dib =
+        TransportDIB::Create(ViewportSizeInBytes(), sequence_num_++);
+    CHECK(dib);
+    bool success = dib->Map();
+    CHECK(success);
+    return dib;
+  }
+
+  static const int kNumBuffers = 2;
+  int front_buffer_;
+  int last_buffer_;
+  int num_free_buffers_;
+  ScopedVector<TransportDIB> dibs_;
+  SkBitmap bitmap_;
+  uint32 sequence_num_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_GPU_COMPOSITOR_SOFTWARE_OUTPUT_DEVICE_H_