Devtools Animations: Add buffer and effect selection to animation timeline

Source/devtools/devtools.gypi

 #
 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #         * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #         * Redistributions in binary form must reproduce the above
@@ skipping 339 matching lines @@
         # Lazy-loaded modules.
         'devtools_accessibility_js_files': [
             'front_end/accessibility/accessibilityNode.css',
             'front_end/accessibility/AccessibilityModel.js',
             'front_end/accessibility/AccessibilitySidebarView.js',
             'front_end/accessibility/AccessibilityStrings.js',
         ],
         'devtools_animation_js_files': [
             'front_end/animation/animationTimeline.css',
             'front_end/animation/AnimationControlPane.js',
+            'front_end/animation/AnimationGroupPreviewUI.js',
             'front_end/animation/AnimationModel.js',
             'front_end/animation/AnimationTimeline.js',
         ],
         'devtools_audits_js_files': [
             'front_end/audits/auditResultTree.css',
             'front_end/audits/auditsPanel.css',
             'front_end/audits/AuditCategories.js',
             'front_end/audits/AuditCategory.js',
             'front_end/audits/AuditController.js',
             'front_end/audits/AuditExtensionCategory.js',
@@ skipping 438 matching lines @@
             'front_end/Images/toolbarItemSelected.png',
             'front_end/Images/touchCursor.png',
             'front_end/Images/touchCursor_2x.png',
             'front_end/Images/updateServiceWorker.svg',
         ],
         'devtools_extension_api_files': [
             'front_end/extensions/ExtensionAPI.js',
         ],
     },
 }