Replace (most) occurrences of mojo::Array<T>() with nullptr.

services/url_response_disk_cache/url_response_disk_cache_impl.cc

 // 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.
 
 #include "services/url_response_disk_cache/url_response_disk_cache_impl.h"
 
 #include <dirent.h>
 #include <fcntl.h>
 #include <sys/types.h>
 
@@ skipping 63 matching lines @@
                    const base::FilePath& trash_dir) {
   // Delete the trash directory.
   task_runner->PostDelayedTask(
       FROM_HERE,
       base::Bind(base::IgnoreResult(&base::DeleteFile), trash_dir, true),
       base::TimeDelta::FromSeconds(kTrashDelayInSeconds));
 }
 
 Array<uint8_t> PathToArray(const base::FilePath& path) {
   if (path.empty())
-    return Array<uint8_t>();
+    return nullptr;
   const std::string& string = path.value();
   auto result = Array<uint8_t>::New(string.size());
   memcpy(&result.front(), string.data(), string.size());
   return result;
 }
 
 // This method remove the query string of an url if one is present. It does
 // match the behavior of the application manager, which connects to the same app
 // if requested twice with different query parameters.
 std::string CanonicalizeURL(const std::string& url) {
@@ skipping 285 matching lines @@
         task_runner_, canonilized_url, staged_response_body_path,
         base::Bind(
             RunCallbackWithSuccess,
             base::Bind(&RunMojoCallbackWithResponse, callback, canonilized_url),
             identifier, request_origin_, canonilized_url,
             base::Passed(GetMinimalResponse(canonilized_url)), db_,
             task_runner_));
     return;
   }
   if (IsInvalidated(entry) || !IsCacheEntryValid(entry)) {
-    callback.Run(URLResponsePtr(), Array<uint8_t>(), Array<uint8_t>());
+    callback.Run(URLResponsePtr(), nullptr, nullptr);
     return;
   }
   callback.Run(entry->response.Pass(),
                PathToArray(base::FilePath(entry->response_body_path)),
                PathToArray(GetConsumerCacheDirectory(
                    base::FilePath(entry->entry_directory))));
   UpdateLastInvalidation(db_, key.Pass(), base::Time::Now());
 }
 
 void URLResponseDiskCacheImpl::Validate(const String& url) {
@@ skipping 114 matching lines @@
       return;
     }
   }
   // We can ignore write error, as it will just force to clear the cache on the
   // next request.
   WriteFile(GetExtractionSentinel(entry_directory), nullptr, 0);
   callback.Run(extraction_directory, consumer_cache_directory);
 }
 
 }  // namespace mojo