[DevTools] Make UI.GlassPane position contentElement for different overlay controls.

third_party/WebKit/Source/devtools/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//third_party/WebKit/public/public_features.gni")
 import("//third_party/WebKit/Source/core/core.gni")
 
 all_devtools_files = [
   "front_end/accessibility/AccessibilityModel.js",
@@ skipping 575 matching lines @@
   "front_end/ui/SyntaxHighlighter.js",
   "front_end/ui/DropDownMenu.js",
   "front_end/ui/dropTarget.css",
   "front_end/ui/DropTarget.js",
   "front_end/ui/emptyWidget.css",
   "front_end/ui/EmptyWidget.js",
   "front_end/ui/filter.css",
   "front_end/ui/FilterBar.js",
   "front_end/ui/ForwardedInputEventHandler.js",
   "front_end/ui/Geometry.js",
+  "front_end/ui/GlassPane.js",
   "front_end/ui/HistoryInput.js",
   "front_end/ui/Icon.js",
   "front_end/ui/infobar.css",
   "front_end/ui/Infobar.js",
   "front_end/ui/InplaceEditor.js",
   "front_end/ui/inspectorCommon.css",
   "front_end/ui/inspectorStyle.css",
   "front_end/ui/inspectorSyntaxHighlight.css",
   "front_end/ui/inspectorSyntaxHighlightDark.css",
   "front_end/ui/InspectorView.js",
@@ skipping 478 matching lines @@
     ".eslintrc.js",
     "devtools-node-modules/",
     "front_end/",
     "scripts/buildbot/run_eslint.py",
     "scripts/local_node/",
     "//testing/scripts/common.py",
     "//testing/scripts/run_devtools_check.py",
     "//testing/xvfb.py",
   ]
 }