Remove uses of base::hash_map from //chrome

chrome/browser/media_galleries/mac/mtp_device_delegate_impl_mac.mm

 // 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.
 
 #include "chrome/browser/media_galleries/mac/mtp_device_delegate_impl_mac.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 279 matching lines @@
   content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
       base::Bind(&MTPDeviceDelegateImplMac::CancelAndDelete,
                  base::Unretained(this)));
 }
 
 void MTPDeviceDelegateImplMac::GetFileInfoImpl(
     const base::FilePath& file_path,
     base::File::Info* file_info,
     base::File::Error* error) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  base::hash_map<base::FilePath::StringType,
-                 base::File::Info>::const_iterator i =
-      file_info_.find(file_path.value());
+  auto i = file_info_.find(file_path.value());
   if (i == file_info_.end()) {
     *error = base::File::FILE_ERROR_NOT_FOUND;
     return;
   }
   *file_info = i->second;
   *error = base::File::FILE_OK;
 }
 
 void MTPDeviceDelegateImplMac::ReadDirectoryImpl(
       const base::FilePath& root,
@@ skipping 256 matching lines @@
   std::string device_name = base::FilePath(device_location).BaseName().value();
   std::string device_id;
   storage_monitor::StorageInfo::Type type;
   bool cracked = storage_monitor::StorageInfo::CrackDeviceId(
       device_name, &type, &device_id);
   DCHECK(cracked);
   DCHECK_EQ(storage_monitor::StorageInfo::MAC_IMAGE_CAPTURE, type);
 
   cb.Run(new MTPDeviceDelegateImplMac(device_id, device_location));
 }