[filesapp] Move Devtools to the end of file_manager_browsertest_base.h

Move DevTools listener to the file_manager_browsertest_base.h (to keep
out of the way of other work that'll go on here).

Tbr: alex
Bug: 1113941
Change-Id: Ie814fda50afef3d1cd19ce7d47ebc8a39a2b0818
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2485373Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818820}

chrome/browser/chromeos/file_manager/file_manager_browsertest_base.h

@@ -196,10 +196,11 @@ class FileManagerBrowserTestBase : public content::DevToolsAgentHostObserver,
   std::unique_ptr<drive::DriveIntegrationServiceFactory::ScopedFactoryForTest>
       service_factory_for_test_;
 
-  std::unique_ptr<NotificationDisplayServiceTester> display_service_;
   std::unique_ptr<arc::FakeFileSystemInstance> arc_file_system_instance_;
 
+  std::unique_ptr<NotificationDisplayServiceTester> display_service_;
   std::unique_ptr<MockFileTasksObserver> file_tasks_observer_;
+  SelectFileDialogExtensionTestFactory* select_factory_;  // Not owned.
 
   base::HistogramTester histograms_;
   base::UserActionTester user_actions_;
@@ -209,9 +210,6 @@ class FileManagerBrowserTestBase : public content::DevToolsAgentHostObserver,
       devtools_agent_;
   uint32_t process_id_ = 0;
 
-  // Not owned.
-  SelectFileDialogExtensionTestFactory* select_factory_;
-
   DISALLOW_COPY_AND_ASSIGN(FileManagerBrowserTestBase);
 };