Refactor the wallpaper encoding to another file/class.

chrome/browser/ui/webui/options2/chromeos/simple_png_encoder.h

+// Copyright (c) 2012 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 CHROME_BROWSER_UI_WEBUI_OPTIONS2_CHROMEOS_SIMPLE_PNG_ENCODER_H_
+#define CHROME_BROWSER_UI_WEBUI_OPTIONS2_CHROMEOS_SIMPLE_PNG_ENCODER_H_
+
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/synchronization/cancellation_flag.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+
+namespace chromeos {
+
+typedef base::Callback<void(
+    scoped_refptr<base::RefCountedBytes>)> EncoderCallback;
+
+// Operation class that encodes existing in-memory image as PNG.
+// It uses NO-COMPRESSION to save time.
+class SimplePngEncoder
+    : public base::RefCountedThreadSafe<SimplePngEncoder> {
+ public:
+  SimplePngEncoder(scoped_refptr<base::RefCountedBytes> data,
+                   SkBitmap image,
+                   base::Closure cancel_callback);
+
+  void Run(EncoderCallback callback);
+
+  void EncodeWallpaper();
+  void Cancel();
+
+ private:
+  friend class base::RefCountedThreadSafe<SimplePngEncoder>;
+
+  ~SimplePngEncoder();
+
+  base::CancellationFlag cancel_flag_;
+
+  // Buffer to store encoded image.
+  scoped_refptr<base::RefCountedBytes> data_;
+  // Original image to encode.
+  SkBitmap image_;
+  base::Closure cancel_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(SimplePngEncoder);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_UI_WEBUI_OPTIONS2_CHROMEOS_SIMPLE_PNG_ENCODER_H_