[Suggestions] Create ImageEncoder, to abstract away image encode/decode.

components/suggestions/image_encoder.h

+// Copyright 2014 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 COMPONENTS_SUGGESTIONS_IMAGE_ENCODER_H_
+#define COMPONENTS_SUGGESTIONS_IMAGE_ENCODER_H_
+
+#include <vector>
+
+#include "base/macros.h"
+
+class SkBitmap;
+
+namespace suggestions {
+
+// A interface to encode/decode images.
+class ImageEncoder {
+ public:
+  ImageEncoder() {}
+  virtual ~ImageEncoder() {}
+
+  // From encoded bytes to SkBitmap. Caller owns the returned pointer.
+  virtual SkBitmap* DecodeImage(
+      const std::vector<unsigned char>& encoded_data) = 0;
+
+  // From SkBitmap to the vector of encoded bytes, |dst|.
+  virtual bool EncodeImage(
+      const SkBitmap& bitmap, std::vector<unsigned char>* dest) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ImageEncoder);
+};
+
+}  // namespace suggestions
+
+#endif  // COMPONENTS_SUGGESTIONS_IMAGE_ENCODER_H_