JPEG decoding: replace ownership comments with std::unique_ptr.

components/suggestions/image_encoder.cc

 // 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.
 
 #include "components/suggestions/image_encoder.h"
 
 #include "ui/gfx/codec/jpeg_codec.h"
 #include "ui/gfx/image/image_skia.h"
 
 namespace suggestions {
 
-SkBitmap* DecodeJPEGToSkBitmap(const void* encoded_data, size_t size) {
+std::unique_ptr<SkBitmap> DecodeJPEGToSkBitmap(const void* encoded_data,
+                                               size_t size) {
   return gfx::JPEGCodec::Decode(static_cast<const unsigned char*>(encoded_data),
                                 size);
 }
 
 bool EncodeSkBitmapToJPEG(const SkBitmap& bitmap,
                           std::vector<unsigned char>* dest) {
   SkAutoLockPixels bitmap_lock(bitmap);
   if (!bitmap.readyToDraw() || bitmap.isNull()) {
     return false;
   }
   return gfx::JPEGCodec::Encode(
       reinterpret_cast<unsigned char*>(bitmap.getAddr32(0, 0)),
       gfx::JPEGCodec::FORMAT_SkBitmap, bitmap.width(), bitmap.height(),
       bitmap.rowBytes(), 100, dest);
 }
 
 }  // namespace suggestions