Revert of DevTools: Remove pageAgent() call from DebuggerModel

Source/devtools/front_end/main/OverlayController.js

-// Copyright 2015 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.
-
-/**
- * @constructor
- */
-WebInspector.OverlayController = function()
-{
-    WebInspector.settings.disablePausedStateOverlay.addChangeListener(this._updateOverlayMessage, this);
-    WebInspector.targetManager.addModelListener(WebInspector.DebuggerModel, WebInspector.DebuggerModel.Events.DebuggerPaused, this._updateOverlayMessage, this);
-    WebInspector.targetManager.addModelListener(WebInspector.DebuggerModel, WebInspector.DebuggerModel.Events.DebuggerResumed, this._updateOverlayMessage, this);
-    WebInspector.targetManager.addModelListener(WebInspector.DebuggerModel, WebInspector.DebuggerModel.Events.GlobalObjectCleared, this._updateOverlayMessage, this);
-}
-
-WebInspector.OverlayController.prototype = {
-
-    /**
-     * @param {!WebInspector.Event} event
-     */
-    _updateOverlayMessage: function(event)
-    {
-        var debuggerModel = /** @type {!WebInspector.DebuggerModel} */ (event.target);
-        var message = debuggerModel.isPaused() && !WebInspector.settings.disablePausedStateOverlay.get() ? WebInspector.UIString("Paused in debugger") : undefined;
-        debuggerModel.target().pageAgent().setOverlayMessage(message);
-    }
-}