Convert //extensions/browser from scoped_ptr to std::unique_ptr

extensions/browser/content_hash_tree.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 "extensions/browser/content_hash_tree.h"
 
-#include "base/memory/scoped_ptr.h"
+#include <memory>
+
 #include "base/stl_util.h"
 #include "crypto/secure_hash.h"
 #include "crypto/sha2.h"
 
 namespace extensions {
 
 std::string ComputeTreeHashRoot(const std::vector<std::string>& leaf_hashes,
                                 int branch_factor) {
   if (leaf_hashes.empty() || branch_factor < 2)
     return std::string();
 
   // The nodes of the tree we're currently operating on.
   std::vector<std::string> current_nodes;
 
   // We avoid having to copy all of the input leaf nodes into |current_nodes|
   // by using a pointer. So the first iteration of the loop this points at
   // |leaf_hashes|, but thereafter it points at |current_nodes|.
   const std::vector<std::string>* current = &leaf_hashes;
 
   // Where we're inserting new hashes computed from the current level.
   std::vector<std::string> parent_nodes;
 
   while (current->size() > 1) {
     // Iterate over the current level of hashes, computing the hash of up to
     // |branch_factor| elements to form the hash of each parent node.
     std::vector<std::string>::const_iterator i = current->begin();
     while (i != current->end()) {
-      scoped_ptr<crypto::SecureHash> hash(
+      std::unique_ptr<crypto::SecureHash> hash(
           crypto::SecureHash::Create(crypto::SecureHash::SHA256));
       for (int j = 0; j < branch_factor && i != current->end(); j++) {
         DCHECK_EQ(i->size(), crypto::kSHA256Length);
         hash->Update(i->data(), i->size());
         ++i;
       }
       parent_nodes.push_back(std::string(crypto::kSHA256Length, 0));
       std::string* output = &(parent_nodes.back());
       hash->Finish(string_as_array(output), output->size());
     }
     current_nodes.swap(parent_nodes);
     parent_nodes.clear();
     current = &current_nodes;
   }
   DCHECK_EQ(1u, current->size());
   return (*current)[0];
 }
 
 }  // namespace extensions