Convert //ios from scoped_ptr to std::unique_ptr.

ios/chrome/browser/favicon/favicon_loader.mm

 // Copyright 2015 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.
 
 #import "ios/chrome/browser/favicon/favicon_loader.h"
 
 #import <UIKit/UIKit.h>
 
 #import "base/mac/foundation_util.h"
 #import "base/mac/scoped_block.h"
@@ skipping 35 matching lines @@
     // or a valid UIImage.
     if (value == [NSNull null])
       return [UIImage imageNamed:@"default_favicon"];
     return base::mac::ObjCCastStrict<UIImage>(value);
   }
 
   // Kick off an async request for the favicon.
   if (favicon_service_) {
     int size = gfx::kFaviconSize * [UIScreen mainScreen].scale;
 
-    scoped_ptr<RequestData> request_data(new RequestData(key, block));
+    std::unique_ptr<RequestData> request_data(new RequestData(key, block));
     favicon_base::FaviconResultsCallback callback =
         base::Bind(&FaviconLoader::OnFaviconAvailable, base::Unretained(this),
                    base::Passed(&request_data));
     favicon_service_->GetFaviconForPageURL(url, types, size, callback,
                                            &cancelable_task_tracker_);
   }
 
   return [UIImage imageNamed:@"default_favicon"];
 }
 
 void FaviconLoader::PurgeCache() {
   DCHECK(thread_checker_.CalledOnValidThread());
   cancelable_task_tracker_.TryCancelAll();
   favicon_cache_.reset(
       [[NSMutableDictionary dictionaryWithCapacity:10] retain]);
 }
 
 void FaviconLoader::OnFaviconAvailable(
-    scoped_ptr<RequestData> request_data,
+    std::unique_ptr<RequestData> request_data,
     const std::vector<favicon_base::FaviconRawBitmapResult>&
         favicon_bitmap_results) {
   DCHECK(request_data);
   DCHECK(thread_checker_.CalledOnValidThread());
   if (favicon_bitmap_results.size() < 1 ||
       !favicon_bitmap_results[0].is_valid()) {
     // Return early if there were no results or if it is invalid, after adding a
     // "no favicon" entry to the cache so that we don't keep trying to fetch a
     // missing favicon over and over.
     [favicon_cache_ setObject:[NSNull null] forKey:request_data->key];
     return;
   }
 
   // The favicon code assumes favicons are PNG-encoded.
   NSData* image_data =
       [NSData dataWithBytes:favicon_bitmap_results[0].bitmap_data->front()
                      length:favicon_bitmap_results[0].bitmap_data->size()];
   UIImage* favicon =
       [UIImage imageWithData:image_data scale:[[UIScreen mainScreen] scale]];
   [favicon_cache_ setObject:favicon forKey:request_data->key];
 
   // Call the block to tell the caller this is complete.
   if (request_data->block)
     (request_data->block.get())(favicon);
 }