mediaview: Hack to avoid Files app to freeze soon after login.

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root_unittest.cc

 // Copyright 2016 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 <string.h>
 
 #include <memory>
 #include <string>
 #include <utility>
 
@@ skipping 297 matching lines @@
                       watcher_callback,
                       base::Bind(
                           [](base::RunLoop* run_loop, base::File::Error error) {
                             EXPECT_EQ(base::File::FILE_OK, error);
                             run_loop->Quit();
                           },
                           &run_loop));
     run_loop.Run();
   }
 
+  // Even if AddWatcher() returns, the watch may not have started. In order to
+  // make installation finish we run the message loop until idle. This depends
+  // on the behavior of FakeFileSystemInstance.
+  //
+  // TODO(crbug.com/698624): Remove the hack to make AddWatcher() return
+  // immediately.
+  base::RunLoop().RunUntilIdle();
+
   EXPECT_EQ(0, num_called);
   fake_file_system_.TriggerWatchers(kAuthority, kDirSpec.document_id,
                                     mojom::ChangeType::CHANGED);
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(1, num_called);
 
   {
     base::RunLoop run_loop;
     root_->RemoveWatcher(
         base::FilePath(FILE_PATH_LITERAL("dir")),
@@ skipping 22 matching lines @@
                       watcher_callback,
                       base::Bind(
                           [](base::RunLoop* run_loop, base::File::Error error) {
                             EXPECT_EQ(base::File::FILE_OK, error);
                             run_loop->Quit();
                           },
                           &run_loop));
     run_loop.Run();
   }
 
+  // Even if AddWatcher() returns, the watch may not have started. In order to
+  // make installation finish we run the message loop until idle. This depends
+  // on the behavior of FakeFileSystemInstance.
+  //
+  // TODO(crbug.com/698624): Remove the hack to make AddWatcher() return
+  // immediately.
+  base::RunLoop().RunUntilIdle();
+
   EXPECT_EQ(0, num_called);
   fake_file_system_.TriggerWatchers(kAuthority, kDirSpec.document_id,
                                     mojom::ChangeType::DELETED);
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(1, num_called);
 
   // Even if the watched file was deleted, the watcher is still alive and we
   // should clean it up.
   {
     base::RunLoop run_loop;
@@ skipping 59 matching lines @@
           [](base::RunLoop* run_loop, const GURL& url) {
             EXPECT_EQ(GURL("content://org.chromium.test/document/dup3-id"),
                       url);
             run_loop->Quit();
           },
           &run_loop));
   run_loop.Run();
 }
 
 }  // namespace arc