DevTools: only set title w/ shortcut via Tooltip manager API.

Source/devtools/front_end/ui/SplitWidget.js

 /*
  * Copyright (C) 2012 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:
  *
  * 1. Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *
@@ skipping 874 matching lines @@
     {
         if (!this._showHideSidebarButton)
             return;
         var sidebarHidden = this._showMode === WebInspector.SplitWidget.ShowMode.OnlyMain;
         this._showHideSidebarButton.classList.toggle("toggled-show", sidebarHidden);
         this._showHideSidebarButton.classList.toggle("toggled-hide", !sidebarHidden);
         this._showHideSidebarButton.classList.toggle("top-sidebar-show-hide-button", !this.isVertical() && !this.isSidebarSecond());
         this._showHideSidebarButton.classList.toggle("right-sidebar-show-hide-button", this.isVertical() && this.isSidebarSecond());
         this._showHideSidebarButton.classList.toggle("bottom-sidebar-show-hide-button", !this.isVertical() && this.isSidebarSecond());
         this._showHideSidebarButton.classList.toggle("left-sidebar-show-hide-button", this.isVertical() && !this.isSidebarSecond());
-        WebInspector.Tooltip.install(this._showHideSidebarButton, sidebarHidden ? WebInspector.UIString("Show %s", this._showHideSidebarButtonTitle) : WebInspector.UIString("Hide %s", this._showHideSidebarButtonTitle));
+        this._showHideSidebarButton.title = sidebarHidden ? WebInspector.UIString("Show %s", this._showHideSidebarButtonTitle) : WebInspector.UIString("Hide %s", this._showHideSidebarButtonTitle);
     },
 
     __proto__: WebInspector.Widget.prototype
 }