Remove file-level 'use strict' from file_manager.

BUG=406995
TEST=none

Review URL: https://codereview.chromium.org/676633002

Cr-Commit-Position: refs/heads/master@{#301082}

102 files changed, 3 insertions, 204 deletions

diff --git a/ui/file_manager/audio_player/elements/audio_player.js b/ui/file_manager/audio_player/elements/audio_player.js
index ee71220..4b5c282 100644
--- a/ui/file_manager/audio_player/elements/audio_player.js
+++ b/ui/file_manager/audio_player/elements/audio_player.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 Polymer('audio-player', {
   /**
    * Child Elements
diff --git a/ui/file_manager/audio_player/js/audio_player.js b/ui/file_manager/audio_player/js/audio_player.js
index 932dee3..a10c93b5 100644
--- a/ui/file_manager/audio_player/js/audio_player.js
+++ b/ui/file_manager/audio_player/js/audio_player.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Overrided metadata worker's path.
  * @type {string}
diff --git a/ui/file_manager/audio_player/js/background.js b/ui/file_manager/audio_player/js/background.js
index 23cf74c..22e1464 100644
--- a/ui/file_manager/audio_player/js/background.js
+++ b/ui/file_manager/audio_player/js/background.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Icon of the audio player.
  * TODO(yoshiki): Consider providing an exact size icon, instead of relying
diff --git a/ui/file_manager/audio_player/js/metadata_worker.js b/ui/file_manager/audio_player/js/metadata_worker.js
index 56ea36c..26af2a1 100644
--- a/ui/file_manager/audio_player/js/metadata_worker.js
+++ b/ui/file_manager/audio_player/js/metadata_worker.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 // Load the worker script of Files.app.
 importScripts(
     'chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/' +
diff --git a/ui/file_manager/file_manager/background/js/app_window_wrapper.js b/ui/file_manager/file_manager/background/js/app_window_wrapper.js
index 6a0cf2b..9fccfce 100644
--- a/ui/file_manager/file_manager/background/js/app_window_wrapper.js
+++ b/ui/file_manager/file_manager/background/js/app_window_wrapper.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Wrapper for an app window.
  *
diff --git a/ui/file_manager/file_manager/background/js/background.js b/ui/file_manager/file_manager/background/js/background.js
index e21cf51..7ae1896 100644
--- a/ui/file_manager/file_manager/background/js/background.js
+++ b/ui/file_manager/file_manager/background/js/background.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Type of a Files.app's instance launch.
  * @enum {number}
diff --git a/ui/file_manager/file_manager/background/js/background_base.js b/ui/file_manager/file_manager/background/js/background_base.js
index bb65302..f0a86a0 100644
--- a/ui/file_manager/file_manager/background/js/background_base.js
+++ b/ui/file_manager/file_manager/background/js/background_base.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Root class of the background page.
  * @constructor
diff --git a/ui/file_manager/file_manager/background/js/device_handler.js b/ui/file_manager/file_manager/background/js/device_handler.js
index ede5409..7c42ce7 100644
--- a/ui/file_manager/file_manager/background/js/device_handler.js
+++ b/ui/file_manager/file_manager/background/js/device_handler.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Handler of device event.
  * @constructor
diff --git a/ui/file_manager/file_manager/background/js/drive_sync_handler.js b/ui/file_manager/file_manager/background/js/drive_sync_handler.js
index 505f926..066972b 100644
--- a/ui/file_manager/file_manager/background/js/drive_sync_handler.js
+++ b/ui/file_manager/file_manager/background/js/drive_sync_handler.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Handler of the background page for the drive sync events.
  * @param {ProgressCenter} progressCenter Progress center to submit the
diff --git a/ui/file_manager/file_manager/background/js/file_operation_handler.js b/ui/file_manager/file_manager/background/js/file_operation_handler.js
index c3dd81b..5ea0d91 100644
--- a/ui/file_manager/file_manager/background/js/file_operation_handler.js
+++ b/ui/file_manager/file_manager/background/js/file_operation_handler.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * An event handler of the background page for file operations.
  * @param {FileBrowserBackground} background Background page.
diff --git a/ui/file_manager/file_manager/background/js/file_operation_manager.js b/ui/file_manager/file_manager/background/js/file_operation_manager.js
index 67b81be..10d6026 100644
--- a/ui/file_manager/file_manager/background/js/file_operation_manager.js
+++ b/ui/file_manager/file_manager/background/js/file_operation_manager.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Utilities for FileOperationManager.
  */
diff --git a/ui/file_manager/file_manager/background/js/progress_center.js b/ui/file_manager/file_manager/background/js/progress_center.js
index a8b1fe2..1fb83b5 100644
--- a/ui/file_manager/file_manager/background/js/progress_center.js
+++ b/ui/file_manager/file_manager/background/js/progress_center.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Progress center at the background page.
  * @constructor
diff --git a/ui/file_manager/file_manager/background/js/volume_manager.js b/ui/file_manager/file_manager/background/js/volume_manager.js
index 1f0704a..41a0c52 100644
--- a/ui/file_manager/file_manager/background/js/volume_manager.js
+++ b/ui/file_manager/file_manager/background/js/volume_manager.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Represents each volume, such as "drive", "download directory", each "USB
  * flush storage", or "mounted zip archive" etc.
diff --git a/ui/file_manager/file_manager/common/js/async_util.js b/ui/file_manager/file_manager/common/js/async_util.js
index dcd03e3..16a1ca2 100644
--- a/ui/file_manager/file_manager/common/js/async_util.js
+++ b/ui/file_manager/file_manager/common/js/async_util.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Namespace for async utility functions.
  */
diff --git a/ui/file_manager/file_manager/common/js/error_util.js b/ui/file_manager/file_manager/common/js/error_util.js
index 15cbc6ff..9fd8f11 100644
--- a/ui/file_manager/file_manager/common/js/error_util.js
+++ b/ui/file_manager/file_manager/common/js/error_util.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * This variable is checked in SelectFileDialogExtensionBrowserTest.
  * @type {number}
diff --git a/ui/file_manager/file_manager/common/js/progress_center_common.js b/ui/file_manager/file_manager/common/js/progress_center_common.js
index 56ff028..dd73d8e 100644
--- a/ui/file_manager/file_manager/common/js/progress_center_common.js
+++ b/ui/file_manager/file_manager/common/js/progress_center_common.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Event of the ProgressCenter class.
  * @enum {string}
diff --git a/ui/file_manager/file_manager/common/js/util.js b/ui/file_manager/file_manager/common/js/util.js
index 0262022..6e73c08 100644
--- a/ui/file_manager/file_manager/common/js/util.js
+++ b/ui/file_manager/file_manager/common/js/util.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Namespace for utility functions.
  */
diff --git a/ui/file_manager/file_manager/common/js/volume_manager_common.js b/ui/file_manager/file_manager/common/js/volume_manager_common.js
index 2d0f729..249969c 100644
--- a/ui/file_manager/file_manager/common/js/volume_manager_common.js
+++ b/ui/file_manager/file_manager/common/js/volume_manager_common.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Namespace for common types shared between VolumeManager and
  * VolumeManagerWrapper.
diff --git a/ui/file_manager/file_manager/foreground/js/app_installer.js b/ui/file_manager/file_manager/foreground/js/app_installer.js
index 4b75bea..7cd7471 100644
--- a/ui/file_manager/file_manager/foreground/js/app_installer.js
+++ b/ui/file_manager/file_manager/foreground/js/app_installer.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Manage the installation of apps.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/cws_container_client.js b/ui/file_manager/file_manager/foreground/js/cws_container_client.js
index 612bbe5..d177630 100644
--- a/ui/file_manager/file_manager/foreground/js/cws_container_client.js
+++ b/ui/file_manager/file_manager/foreground/js/cws_container_client.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {WebView} webView Web View tag.
  * @param {?string} ext File extension.
diff --git a/ui/file_manager/file_manager/foreground/js/directory_contents.js b/ui/file_manager/file_manager/foreground/js/directory_contents.js
index aec6b15..5aa0678 100644
--- a/ui/file_manager/file_manager/foreground/js/directory_contents.js
+++ b/ui/file_manager/file_manager/foreground/js/directory_contents.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Scanner of the entries.
  * @constructor
diff --git a/ui/file_manager/file_manager/foreground/js/directory_model.js b/ui/file_manager/file_manager/foreground/js/directory_model.js
index f620209..ac27ae8 100644
--- a/ui/file_manager/file_manager/foreground/js/directory_model.js
+++ b/ui/file_manager/file_manager/foreground/js/directory_model.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 // If directory files changes too often, don't rescan directory more than once
 // per specified interval
 var SIMULTANEOUS_RESCAN_INTERVAL = 500;
diff --git a/ui/file_manager/file_manager/foreground/js/file_manager.js b/ui/file_manager/file_manager/foreground/js/file_manager.js
index 40931f9..40db19e 100644
--- a/ui/file_manager/file_manager/foreground/js/file_manager.js
+++ b/ui/file_manager/file_manager/foreground/js/file_manager.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * FileManager constructor.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/file_manager_commands.js b/ui/file_manager/file_manager/foreground/js/file_manager_commands.js
index a1ee73c..f45c70b 100644
--- a/ui/file_manager/file_manager/foreground/js/file_manager_commands.js
+++ b/ui/file_manager/file_manager/foreground/js/file_manager_commands.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * TODO(dzvorygin): Here we use this hack, since 'hidden' is standard
  * attribute and we can't use it's setter as usual.
diff --git a/ui/file_manager/file_manager/foreground/js/file_selection.js b/ui/file_manager/file_manager/foreground/js/file_selection.js
index 7d05387..86df259 100644
--- a/ui/file_manager/file_manager/foreground/js/file_selection.js
+++ b/ui/file_manager/file_manager/foreground/js/file_selection.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * The current selection object.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/file_tasks.js b/ui/file_manager/file_manager/foreground/js/file_tasks.js
index fcf383a..d8a4537 100644
--- a/ui/file_manager/file_manager/foreground/js/file_tasks.js
+++ b/ui/file_manager/file_manager/foreground/js/file_tasks.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * This object encapsulates everything related to tasks execution.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/file_transfer_controller.js b/ui/file_manager/file_manager/foreground/js/file_transfer_controller.js
index f37baeb..fc43cc1 100644
--- a/ui/file_manager/file_manager/foreground/js/file_transfer_controller.js
+++ b/ui/file_manager/file_manager/foreground/js/file_transfer_controller.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Global (placed in the window object) variable name to hold internal
  * file dragging information. Needed to show visual feedback while dragging
diff --git a/ui/file_manager/file_manager/foreground/js/file_type.js b/ui/file_manager/file_manager/foreground/js/file_type.js
index 046a716..f82a3d1 100644
--- a/ui/file_manager/file_manager/foreground/js/file_type.js
+++ b/ui/file_manager/file_manager/foreground/js/file_type.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Namespace object for file type utility functions.
  */
diff --git a/ui/file_manager/file_manager/foreground/js/file_watcher.js b/ui/file_manager/file_manager/foreground/js/file_watcher.js
index dc59e70..ed43e41 100644
--- a/ui/file_manager/file_manager/foreground/js/file_watcher.js
+++ b/ui/file_manager/file_manager/foreground/js/file_watcher.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Watches for changes in the tracked directory, including local metadata
  * changes.
diff --git a/ui/file_manager/file_manager/foreground/js/main.js b/ui/file_manager/file_manager/foreground/js/main.js
index 140b2e0..f624b50 100644
--- a/ui/file_manager/file_manager/foreground/js/main.js
+++ b/ui/file_manager/file_manager/foreground/js/main.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @type {FileManager}
  */
diff --git a/ui/file_manager/file_manager/foreground/js/main_scripts.js b/ui/file_manager/file_manager/foreground/js/main_scripts.js
index d6b0b29..4fe9dec 100644
--- a/ui/file_manager/file_manager/foreground/js/main_scripts.js
+++ b/ui/file_manager/file_manager/foreground/js/main_scripts.js
@@ -65,6 +65,7 @@
 
 (function() {
 // 'strict mode' is invoked for this scope.
+'use strict';
 
 // error_util.js must be loaded before all other Files.app's scripts.
 //<include src="../../common/js/error_util.js">
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/byte_reader.js b/ui/file_manager/file_manager/foreground/js/metadata/byte_reader.js
index e422bf5..5bf28a3 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/byte_reader.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/byte_reader.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @constructor
  * @param {ArrayBuffer} arrayBuffer An array of buffers to be read from.
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/exif_parser.js b/ui/file_manager/file_manager/foreground/js/metadata/exif_parser.js
index 9d9e3ecf..fafcc79 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/exif_parser.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/exif_parser.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 var EXIF_MARK_SOI = 0xffd8;  // Start of image data.
 var EXIF_MARK_SOS = 0xffda;  // Start of "stream" (the actual image data).
 var EXIF_MARK_SOF = 0xffc0;  // Start of "frame"
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/function_parallel.js b/ui/file_manager/file_manager/foreground/js/metadata/function_parallel.js
index 719343b..531ee4f 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/function_parallel.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/function_parallel.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @class FunctionSequence to invoke steps in sequence
  *
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/function_sequence.js b/ui/file_manager/file_manager/foreground/js/metadata/function_sequence.js
index 6a1bf08..85ffe95 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/function_sequence.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/function_sequence.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @class FunctionSequence to invoke steps in sequence
  *
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/id3_parser.js b/ui/file_manager/file_manager/foreground/js/metadata/id3_parser.js
index 05a541d..98ff5e6 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/id3_parser.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/id3_parser.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Protocol + host parts of extension URL.
  * @type {string}
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/image_parsers.js b/ui/file_manager/file_manager/foreground/js/metadata/image_parsers.js
index 8a3ba07..bb60457 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/image_parsers.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/image_parsers.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /* Base class for image metadata parsers that only need to look at a short
   fragment at the start of the file */
 function SimpleImageParser(parent, type, urlFilter, headerSize) {
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/metadata_cache.js b/ui/file_manager/file_manager/foreground/js/metadata/metadata_cache.js
index 8de5921e..092d9ce 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/metadata_cache.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/metadata_cache.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * MetadataCache is a map from Entry to an object containing properties.
  * Properties are divided by types, and all properties of one type are accessed
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/metadata_dispatcher.js b/ui/file_manager/file_manager/foreground/js/metadata/metadata_dispatcher.js
index 9f88668..07ee39c 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/metadata_dispatcher.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/metadata_dispatcher.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Protocol + host parts of extension URL.
  * @type {string}
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/metadata_parser.js b/ui/file_manager/file_manager/foreground/js/metadata/metadata_parser.js
index 087eb42..adc0ea7 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/metadata_parser.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/metadata_parser.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {MetadataDispatcher} parent Parent object.
  * @param {string} type Parser type.
diff --git a/ui/file_manager/file_manager/foreground/js/metadata/mpeg_parser.js b/ui/file_manager/file_manager/foreground/js/metadata/mpeg_parser.js
index 36ede26..63caced 100644
--- a/ui/file_manager/file_manager/foreground/js/metadata/mpeg_parser.js
+++ b/ui/file_manager/file_manager/foreground/js/metadata/mpeg_parser.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {MetadataDispatcher} parent Parent object.
  * @constructor
diff --git a/ui/file_manager/file_manager/foreground/js/mouse_inactivity_watcher.js b/ui/file_manager/file_manager/foreground/js/mouse_inactivity_watcher.js
index 7f0da33..e19b82a 100644
--- a/ui/file_manager/file_manager/foreground/js/mouse_inactivity_watcher.js
+++ b/ui/file_manager/file_manager/foreground/js/mouse_inactivity_watcher.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * A controller class detects mouse inactivity and hides "tool" elements.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/navigation_list_model.js b/ui/file_manager/file_manager/foreground/js/navigation_list_model.js
index 62b031d..5195f86 100644
--- a/ui/file_manager/file_manager/foreground/js/navigation_list_model.js
+++ b/ui/file_manager/file_manager/foreground/js/navigation_list_model.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Base item of NavigationListModel. Should not be created directly.
  * @param {string} label Label.
diff --git a/ui/file_manager/file_manager/foreground/js/progress_center_item_group.js b/ui/file_manager/file_manager/foreground/js/progress_center_item_group.js
index d556a81..4958190 100644
--- a/ui/file_manager/file_manager/foreground/js/progress_center_item_group.js
+++ b/ui/file_manager/file_manager/foreground/js/progress_center_item_group.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Group of progress item in the progress center panels.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/search_controller.js b/ui/file_manager/file_manager/foreground/js/search_controller.js
index 23c9bd2..1340c6d 100644
--- a/ui/file_manager/file_manager/foreground/js/search_controller.js
+++ b/ui/file_manager/file_manager/foreground/js/search_controller.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Controller for searching.
  * @param {SearchBox} searchBox Search box UI element.
diff --git a/ui/file_manager/file_manager/foreground/js/share_client.js b/ui/file_manager/file_manager/foreground/js/share_client.js
index 36033cc..f332dd6 100644
--- a/ui/file_manager/file_manager/foreground/js/share_client.js
+++ b/ui/file_manager/file_manager/foreground/js/share_client.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {WebView} webView Web View tag.
  * @param {string} url Share Url for an entry.
diff --git a/ui/file_manager/file_manager/foreground/js/thumbnail_loader.js b/ui/file_manager/file_manager/foreground/js/thumbnail_loader.js
index 0102947..51d1115 100644
--- a/ui/file_manager/file_manager/foreground/js/thumbnail_loader.js
+++ b/ui/file_manager/file_manager/foreground/js/thumbnail_loader.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Loads a thumbnail using provided url. In CANVAS mode, loaded images
  * are attached as <canvas> element, while in IMAGE mode as <img>.
diff --git a/ui/file_manager/file_manager/foreground/js/ui/combobutton.js b/ui/file_manager/file_manager/foreground/js/ui/combobutton.js
index 85f962d..e6a84b4 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/combobutton.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/combobutton.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @fileoverview This implements a combobutton control.
  */
diff --git a/ui/file_manager/file_manager/foreground/js/ui/commandbutton.js b/ui/file_manager/file_manager/foreground/js/ui/commandbutton.js
index 27d01ad..570dc57 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/commandbutton.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/commandbutton.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @fileoverview This implements a common button control, bound to command.
  */
diff --git a/ui/file_manager/file_manager/foreground/js/ui/conflict_dialog.js b/ui/file_manager/file_manager/foreground/js/ui/conflict_dialog.js
index 3c80530..44af485 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/conflict_dialog.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/conflict_dialog.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Dialog to confirm the operation for conflicted file operations.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/ui/default_action_dialog.js b/ui/file_manager/file_manager/foreground/js/ui/default_action_dialog.js
index cba4e6a..47bab22 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/default_action_dialog.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/default_action_dialog.js
@@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
-
 /**
  * DefaultActionDialog contains a message, a list box, an ok button, and a
  * cancel button.
diff --git a/ui/file_manager/file_manager/foreground/js/ui/dialog_footer.js b/ui/file_manager/file_manager/foreground/js/ui/dialog_footer.js
index 13849f1..758ce92 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/dialog_footer.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/dialog_footer.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Footer shown when the Files.app is opened as a file/folder selecting dialog.
  * @param {DialogType} dialogType Dialog type.
diff --git a/ui/file_manager/file_manager/foreground/js/ui/directory_tree.js b/ui/file_manager/file_manager/foreground/js/ui/directory_tree.js
index f316a57..b7c094d 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/directory_tree.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/directory_tree.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 ////////////////////////////////////////////////////////////////////////////////
 // DirectoryTreeBase
 
diff --git a/ui/file_manager/file_manager/foreground/js/ui/drag_selector.js b/ui/file_manager/file_manager/foreground/js/ui/drag_selector.js
index ba145bf..9ab27c8 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/drag_selector.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/drag_selector.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Drag selector used on the file list or the grid table.
  * TODO(hirono): Support drag selection for grid view. crbug.com/224832
diff --git a/ui/file_manager/file_manager/foreground/js/ui/drive_banners.js b/ui/file_manager/file_manager/foreground/js/ui/drive_banners.js
index 4776e40..4f85191 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/drive_banners.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/drive_banners.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Responsible for showing following banners in the file list.
  *  - WelcomeBanner
diff --git a/ui/file_manager/file_manager/foreground/js/ui/error_dialog.js b/ui/file_manager/file_manager/foreground/js/ui/error_dialog.js
index 96bb4e1..63515a6 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/error_dialog.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/error_dialog.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {HTMLElement} parentNode Node to be parent for this dialog.
  * @constructor
diff --git a/ui/file_manager/file_manager/foreground/js/ui/file_grid.js b/ui/file_manager/file_manager/foreground/js/ui/file_grid.js
index 80f60ff..123d5ad 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/file_grid.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/file_grid.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * FileGrid constructor.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/ui/file_manager_dialog_base.js b/ui/file_manager/file_manager/foreground/js/ui/file_manager_dialog_base.js
index 5d56a74..bb7c83a 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/file_manager_dialog_base.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/file_manager_dialog_base.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * This class is an extended class, to manage the status of the dialogs.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/ui/file_manager_ui.js b/ui/file_manager/file_manager/foreground/js/ui/file_manager_ui.js
index 3e25139..48c1938 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/file_manager_ui.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/file_manager_ui.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * The root of the file manager's view managing the DOM of Files.app.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/ui/file_table.js b/ui/file_manager/file_manager/foreground/js/ui/file_table.js
index 34e36d4..3064618 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/file_table.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/file_table.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Namespace for utility functions.
  */
diff --git a/ui/file_manager/file_manager/foreground/js/ui/location_line.js b/ui/file_manager/file_manager/foreground/js/ui/location_line.js
index 3aeb0bb..25fbdcf 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/location_line.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/location_line.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * TODO(hirono): Remove metadataCache and volumeManager dependencies from the UI
  * class.
diff --git a/ui/file_manager/file_manager/foreground/js/ui/multi_profile_share_dialog.js b/ui/file_manager/file_manager/foreground/js/ui/multi_profile_share_dialog.js
index 19362b0..a1cb232 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/multi_profile_share_dialog.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/multi_profile_share_dialog.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Dialog to confirm the share between profiles.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/ui/preview_panel.js b/ui/file_manager/file_manager/foreground/js/ui/preview_panel.js
index 8def6fb..47cd2c7 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/preview_panel.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/preview_panel.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * PreviewPanel UI class.
  * @param {Element} element DOM Element of preview panel.
diff --git a/ui/file_manager/file_manager/foreground/js/ui/progress_center_panel.js b/ui/file_manager/file_manager/foreground/js/ui/progress_center_panel.js
index 99686a7..94de1f4 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/progress_center_panel.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/progress_center_panel.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Item element of the progress center.
  * @param {Document} document Document which the new item belongs to.
diff --git a/ui/file_manager/file_manager/foreground/js/ui/scrollbar.js b/ui/file_manager/file_manager/foreground/js/ui/scrollbar.js
index 755fbec..1430473 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/scrollbar.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/scrollbar.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Creates a new scroll bar element.
  * @extends {HTMLDivElement}
diff --git a/ui/file_manager/file_manager/foreground/js/ui/search_box.js b/ui/file_manager/file_manager/foreground/js/ui/search_box.js
index a066bfa..32b0bb3 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/search_box.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/search_box.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Search box.
  *
diff --git a/ui/file_manager/file_manager/foreground/js/ui/share_dialog.js b/ui/file_manager/file_manager/foreground/js/ui/share_dialog.js
index cd5831d..15feb5a 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/share_dialog.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/share_dialog.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {HTMLElement} parentNode Node to be parent for this dialog.
  * @constructor
diff --git a/ui/file_manager/file_manager/foreground/js/ui/suggest_apps_dialog.js b/ui/file_manager/file_manager/foreground/js/ui/suggest_apps_dialog.js
index fc42c1c..fd4f5b8 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/suggest_apps_dialog.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/suggest_apps_dialog.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * SuggestAppsDialog contains a list box to select an app to be opened the file
  * with. This dialog should be used as action picker for file operations.
diff --git a/ui/file_manager/file_manager/foreground/js/ui/tree.css.js b/ui/file_manager/file_manager/foreground/js/ui/tree.css.js
index 6b89acb..08c6c5c 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/tree.css.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/tree.css.js
@@ -2,13 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Custom version of chrome://resources/css/tree.css.js, adding support for
  * inverted arrow icons.
  */
 (function() {
+  'use strict';
+
   /**
    * @type {number}
    * @const
diff --git a/ui/file_manager/gallery/js/background.js b/ui/file_manager/gallery/js/background.js
index 0b51c04..591d466 100644
--- a/ui/file_manager/gallery/js/background.js
+++ b/ui/file_manager/gallery/js/background.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {Object.<string, string>} stringData String data.
  * @param {VolumeManager} volumeManager Volume manager.
diff --git a/ui/file_manager/gallery/js/error_banner.js b/ui/file_manager/gallery/js/error_banner.js
index ec63c98..3a23a4f 100644
--- a/ui/file_manager/gallery/js/error_banner.js
+++ b/ui/file_manager/gallery/js/error_banner.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {Element} container Content container.
  * @constructor
diff --git a/ui/file_manager/gallery/js/gallery.js b/ui/file_manager/gallery/js/gallery.js
index 04e539f..3a20e4d 100644
--- a/ui/file_manager/gallery/js/gallery.js
+++ b/ui/file_manager/gallery/js/gallery.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Called from the main frame when unloading.
  * @param {boolean=} opt_exiting True if the app is exiting.
diff --git a/ui/file_manager/gallery/js/gallery_item.js b/ui/file_manager/gallery/js/gallery_item.js
index f5c2b6f..994d5a2 100644
--- a/ui/file_manager/gallery/js/gallery_item.js
+++ b/ui/file_manager/gallery/js/gallery_item.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Object representing an image item (a photo).
  *
diff --git a/ui/file_manager/gallery/js/image_editor/commands.js b/ui/file_manager/gallery/js/image_editor/commands.js
index 8635505..fdde44f 100644
--- a/ui/file_manager/gallery/js/image_editor/commands.js
+++ b/ui/file_manager/gallery/js/image_editor/commands.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Command queue is the only way to modify images.
  * Supports undo/redo.
diff --git a/ui/file_manager/gallery/js/image_editor/exif_encoder.js b/ui/file_manager/gallery/js/image_editor/exif_encoder.js
index cc9c06b..80fdef8 100644
--- a/ui/file_manager/gallery/js/image_editor/exif_encoder.js
+++ b/ui/file_manager/gallery/js/image_editor/exif_encoder.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 // TODO:(kaznacheev) Share the EXIF constants with exif_parser.js
 var EXIF_MARK_SOS = 0xffda;  // Start of "stream" (the actual image data).
 var EXIF_MARK_SOI = 0xffd8;  // Start of image data.
diff --git a/ui/file_manager/gallery/js/image_editor/filter.js b/ui/file_manager/gallery/js/image_editor/filter.js
index d61b895..87c0467 100644
--- a/ui/file_manager/gallery/js/image_editor/filter.js
+++ b/ui/file_manager/gallery/js/image_editor/filter.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * A namespace for image filter utilities.
  */
diff --git a/ui/file_manager/gallery/js/image_editor/image_adjust.js b/ui/file_manager/gallery/js/image_editor/image_adjust.js
index 1794b97..0a7e306 100644
--- a/ui/file_manager/gallery/js/image_editor/image_adjust.js
+++ b/ui/file_manager/gallery/js/image_editor/image_adjust.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * The base class for simple filters that only modify the image content
  * but do not modify the image dimensions.
diff --git a/ui/file_manager/gallery/js/image_editor/image_buffer.js b/ui/file_manager/gallery/js/image_editor/image_buffer.js
index 0526bca..6d28f62 100644
--- a/ui/file_manager/gallery/js/image_editor/image_buffer.js
+++ b/ui/file_manager/gallery/js/image_editor/image_buffer.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * A stack of overlays that display itself and handle mouse events.
  * TODO(kaznacheev) Consider disbanding this class and moving
diff --git a/ui/file_manager/gallery/js/image_editor/image_editor.js b/ui/file_manager/gallery/js/image_editor/image_editor.js
index 37a3bb7..3836188 100644
--- a/ui/file_manager/gallery/js/image_editor/image_editor.js
+++ b/ui/file_manager/gallery/js/image_editor/image_editor.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * ImageEditor is the top level object that holds together and connects
  * everything needed for image editing.
diff --git a/ui/file_manager/gallery/js/image_editor/image_encoder.js b/ui/file_manager/gallery/js/image_editor/image_encoder.js
index c043c50..0cc5e65 100644
--- a/ui/file_manager/gallery/js/image_editor/image_encoder.js
+++ b/ui/file_manager/gallery/js/image_editor/image_encoder.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * A namespace class for image encoding functions. All methods are static.
  */
diff --git a/ui/file_manager/gallery/js/image_editor/image_transform.js b/ui/file_manager/gallery/js/image_editor/image_transform.js
index d73e409..da2ec75 100644
--- a/ui/file_manager/gallery/js/image_editor/image_transform.js
+++ b/ui/file_manager/gallery/js/image_editor/image_transform.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Crop mode.
  *
diff --git a/ui/file_manager/gallery/js/image_editor/image_util.js b/ui/file_manager/gallery/js/image_editor/image_util.js
index eaa1608..7191ee4 100644
--- a/ui/file_manager/gallery/js/image_editor/image_util.js
+++ b/ui/file_manager/gallery/js/image_editor/image_util.js
@@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
-
 // Namespace object for the utilities.
 function ImageUtil() {}
 
diff --git a/ui/file_manager/gallery/js/image_editor/image_view.js b/ui/file_manager/gallery/js/image_editor/image_view.js
index 2f1f6b6..0b84fe0 100644
--- a/ui/file_manager/gallery/js/image_editor/image_view.js
+++ b/ui/file_manager/gallery/js/image_editor/image_view.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * The overlay displaying the image.
  *
diff --git a/ui/file_manager/gallery/js/image_editor/viewport.js b/ui/file_manager/gallery/js/image_editor/viewport.js
index f9dea70..54ea128 100644
--- a/ui/file_manager/gallery/js/image_editor/viewport.js
+++ b/ui/file_manager/gallery/js/image_editor/viewport.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Viewport class controls the way the image is displayed (scale, offset etc).
  * @constructor
diff --git a/ui/file_manager/gallery/js/metadata_worker.js b/ui/file_manager/gallery/js/metadata_worker.js
index 56ea36c..26af2a1 100644
--- a/ui/file_manager/gallery/js/metadata_worker.js
+++ b/ui/file_manager/gallery/js/metadata_worker.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 // Load the worker script of Files.app.
 importScripts(
     'chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/' +
diff --git a/ui/file_manager/gallery/js/mosaic_mode.js b/ui/file_manager/gallery/js/mosaic_mode.js
index a19b50a..900c6f3 100644
--- a/ui/file_manager/gallery/js/mosaic_mode.js
+++ b/ui/file_manager/gallery/js/mosaic_mode.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {Element} container Content container.
  * @param {ErrorBanner} errorBanner Error banner.
diff --git a/ui/file_manager/gallery/js/ribbon.js b/ui/file_manager/gallery/js/ribbon.js
index 4fc44b6..acbc4f9 100644
--- a/ui/file_manager/gallery/js/ribbon.js
+++ b/ui/file_manager/gallery/js/ribbon.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Scrollable thumbnail ribbon at the bottom of the Gallery in the Slide mode.
  *
diff --git a/ui/file_manager/gallery/js/slide_mode.js b/ui/file_manager/gallery/js/slide_mode.js
index 1f0edc2..974fb97 100644
--- a/ui/file_manager/gallery/js/slide_mode.js
+++ b/ui/file_manager/gallery/js/slide_mode.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Slide mode displays a single image and has a set of controls to navigate
  * between the images and to edit an image.
diff --git a/ui/file_manager/image_loader/background.js b/ui/file_manager/image_loader/background.js
index 028a082..bdfac1c 100644
--- a/ui/file_manager/image_loader/background.js
+++ b/ui/file_manager/image_loader/background.js
@@ -2,7 +2,5 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 // Load the extension.
 ImageLoader.getInstance();
diff --git a/ui/file_manager/image_loader/cache.js b/ui/file_manager/image_loader/cache.js
index 5bdb2be..478bccd 100644
--- a/ui/file_manager/image_loader/cache.js
+++ b/ui/file_manager/image_loader/cache.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Persistent cache storing images in an indexed database on the hard disk.
  * @constructor
diff --git a/ui/file_manager/image_loader/image_loader.js b/ui/file_manager/image_loader/image_loader.js
index e45c084..abd183d 100644
--- a/ui/file_manager/image_loader/image_loader.js
+++ b/ui/file_manager/image_loader/image_loader.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Loads and resizes an image.
  * @constructor
diff --git a/ui/file_manager/image_loader/image_loader_client.js b/ui/file_manager/image_loader/image_loader_client.js
index 6dfef8e..88bdaaf 100644
--- a/ui/file_manager/image_loader/image_loader_client.js
+++ b/ui/file_manager/image_loader/image_loader_client.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Client used to connect to the remote ImageLoader extension. Client class runs
  * in the extension, where the client.js is included (eg. Files.app).
diff --git a/ui/file_manager/image_loader/request.js b/ui/file_manager/image_loader/request.js
index 1b1f0df..767b878 100644
--- a/ui/file_manager/image_loader/request.js
+++ b/ui/file_manager/image_loader/request.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @typedef {{
  *   cache: (boolean|undefined),
diff --git a/ui/file_manager/image_loader/scheduler.js b/ui/file_manager/image_loader/scheduler.js
index 844a122..b0f841b 100644
--- a/ui/file_manager/image_loader/scheduler.js
+++ b/ui/file_manager/image_loader/scheduler.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Scheduler for requests. Fetches requests from a queue and processes them
  * synchronously, taking into account priorities. The highest priority is 0.
diff --git a/ui/file_manager/video_player/js/background.js b/ui/file_manager/video_player/js/background.js
index 3e97266..03e5801 100644
--- a/ui/file_manager/video_player/js/background.js
+++ b/ui/file_manager/video_player/js/background.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 // Stores the app windows OLNY for test purpose.
 // We SHOULD NOT use it as it is except for test, since the files which have
 // the same name will be overridden each other.
diff --git a/ui/file_manager/video_player/js/cast/cast_extension_discoverer.js b/ui/file_manager/video_player/js/cast/cast_extension_discoverer.js
index b2ff50d..fe23cb9 100644
--- a/ui/file_manager/video_player/js/cast/cast_extension_discoverer.js
+++ b/ui/file_manager/video_player/js/cast/cast_extension_discoverer.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Discover the ID of installed cast extension.
  * @constructor
diff --git a/ui/file_manager/video_player/js/cast/cast_video_element.js b/ui/file_manager/video_player/js/cast/cast_video_element.js
index 53abbd0..a2ffb39 100644
--- a/ui/file_manager/video_player/js/cast/cast_video_element.js
+++ b/ui/file_manager/video_player/js/cast/cast_video_element.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Interval for updating media info (in ms).
  * @type {number}
diff --git a/ui/file_manager/video_player/js/cast/caster.js b/ui/file_manager/video_player/js/cast/caster.js
index e7dfaff..cf718e2 100644
--- a/ui/file_manager/video_player/js/cast/caster.js
+++ b/ui/file_manager/video_player/js/cast/caster.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 // This hack prevents a bug on the cast extension.
 // TODO(yoshiki): Remove this once the cast extension supports Chrome apps.
 // Although localStorage in Chrome app is not supported, but it's used in the
diff --git a/ui/file_manager/video_player/js/cast/media_manager.js b/ui/file_manager/video_player/js/cast/media_manager.js
index dbf8b8d..28e729d 100644
--- a/ui/file_manager/video_player/js/cast/media_manager.js
+++ b/ui/file_manager/video_player/js/cast/media_manager.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * Media manager class.
  * This class supports the information for the media file.
diff --git a/ui/file_manager/video_player/js/error_util.js b/ui/file_manager/video_player/js/error_util.js
index d3270e8..597a239 100644
--- a/ui/file_manager/video_player/js/error_util.js
+++ b/ui/file_manager/video_player/js/error_util.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * This variable is checked in SelectFileDialogExtensionBrowserTest.
  * @type {number}
diff --git a/ui/file_manager/video_player/js/media_controls.js b/ui/file_manager/video_player/js/media_controls.js
index a565cc4..efe0231 100644
--- a/ui/file_manager/video_player/js/media_controls.js
+++ b/ui/file_manager/video_player/js/media_controls.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @fileoverview MediaControls class implements media playback controls
  * that exist outside of the audio/video HTML element.
diff --git a/ui/file_manager/video_player/js/video_player.js b/ui/file_manager/video_player/js/video_player.js
index cd5dc02..1c6e04a 100644
--- a/ui/file_manager/video_player/js/video_player.js
+++ b/ui/file_manager/video_player/js/video_player.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-'use strict';
-
 /**
  * @param {Element} playerContainer Main container.
  * @param {Element} videoContainer Container for the video element.