Source/WebInspectorUI/UserInterface/ContentViewContainer.js - external/github.com/WebKit/webkit - Git at Google

 /*
  * Copyright (C) 2013 Apple 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */

 WebInspector.ContentViewContainer = function(element)
 {
     WebInspector.Object.call(this);

     this._element = element || document.createElement("div");
     this._element.classList.add(WebInspector.ContentViewContainer.StyleClassName);

     this._backForwardList = [];
     this._currentIndex = -1;
 };

 WebInspector.ContentViewContainer.StyleClassName = "content-view-container";

 WebInspector.ContentViewContainer.Event = {
     CurrentContentViewDidChange: "content-view-container-current-content-view-did-change"
 };

 WebInspector.ContentViewContainer.prototype = {
     constructor: WebInspector.ContentViewContainer,

     // Public

     get element()
     {
         return this._element;
     },

     get currentIndex()
     {
         return this._currentIndex;
     },

     get backForwardList()
     {
         return this._backForwardList;
     },

     get currentContentView()
     {
         if (this._currentIndex < 0 || this._currentIndex > this._backForwardList.length - 1)
             return null;
         return this._backForwardList[this._currentIndex];
     },

     updateLayout: function()
     {
         var currentContentView = this.currentContentView;
         if (currentContentView)
             currentContentView.updateLayout();
     },

     contentViewForRepresentedObject: function(representedObject, onlyExisting)
     {
         console.assert(representedObject);
         if (!representedObject)
             return null;

         // Iterate over all the known content views for the representedObject (if any) and find one that doesn't
         // have a parent container or has this container as its parent.
         var contentView = null;
         for (var i = 0; representedObject.__contentViews && i < representedObject.__contentViews.length; ++i) {
             var currentContentView = representedObject.__contentViews[i];
             if (!currentContentView._parentContainer || currentContentView._parentContainer === this) {
                 contentView = currentContentView;
                 break;
             }
         }

         console.assert(!contentView || contentView instanceof WebInspector.ContentView);
         if (contentView instanceof WebInspector.ContentView)
             return contentView;

         // Return early to avoid creating a new content view when onlyExisting is true.
         if (onlyExisting)
             return null;

         try {
             // No existing content view found, make a new one.
             contentView = new WebInspector.ContentView(representedObject);
         } catch (e) {
             console.error(e);
             return null;
         }

         // Remember this content view for future calls.
         if (!representedObject.__contentViews)
             representedObject.__contentViews = [];
         representedObject.__contentViews.push(contentView);

         return contentView;
     },

     showContentViewForRepresentedObject: function(representedObject)
     {
         var contentView = this.contentViewForRepresentedObject(representedObject);
         if (!contentView)
             return null;

         this.showContentView(contentView);

         return contentView;
     },

     showContentView: function(contentView)
     {
         console.assert(contentView instanceof WebInspector.ContentView);
         if (!(contentView instanceof WebInspector.ContentView))
             return null;

         // Don't allow showing a content view that is already associated with another container.
         // Showing a content view that is already associated with this container is allowed.
         console.assert(!contentView.parentContainer || contentView.parentContainer === this);
         if (contentView.parentContainer && contentView.parentContainer !== this)
             return null;

         // Don't do anything if the content view is already the current content view.
         var currentContentView = this.currentContentView;
         if (currentContentView === contentView)
             return contentView;

         // Showing a content view will truncate the back/forward list after the current index and insert the content view
         // at the end of the list. Finally, the current index will be updated to point to the end of the back/forward list.

         // Increment the current index to where we will insert the content view.
         var newIndex = this._currentIndex + 1;

         // Insert the content view at the new index. This will remove any content views greater than or equal to the index.
         var removedItems = this._backForwardList.splice(newIndex, this._backForwardList.length - newIndex, contentView);

         console.assert(newIndex === this._backForwardList.length - 1);
         console.assert(this._backForwardList[newIndex] === contentView);

         // Disassociate with the removed content views.
         for (var i = 0; i < removedItems.length; ++i) {
             // Skip disassociation if this content view is still in the back/forward list.
             if (this._backForwardList.contains(contentView))
                 continue;

             this._disassociateFromContentView(removedItems[i]);
         }

         // Associate with the new content view.
         contentView._parentContainer = this;

         this.showBackForwardEntry(newIndex);

         return contentView;
     },

     showBackForwardEntry: function(index)
     {
         console.assert(index >= 0 && index <= this._backForwardList.length - 1);
         if (index < 0 || index > this._backForwardList.length - 1)
             return;

         if (this._currentIndex === index)
             return;

         // Hide the currently visible content view.
         var currentContentView = this.currentContentView;
         if (currentContentView)
             this._hideContentView(currentContentView);

         this._currentIndex = index;

         this._showContentView(this.currentContentView);

         this.dispatchEventToListeners(WebInspector.ContentViewContainer.Event.CurrentContentViewDidChange);
     },

     replaceContentView: function(oldContentView, newContentView)
     {
         console.assert(oldContentView instanceof WebInspector.ContentView);
         if (!(oldContentView instanceof WebInspector.ContentView))
             return;

         console.assert(newContentView instanceof WebInspector.ContentView);
         if (!(newContentView instanceof WebInspector.ContentView))
             return;

         console.assert(oldContentView.parentContainer === this);
         if (oldContentView.parentContainer !== this)
             return;

         console.assert(!newContentView.parentContainer || newContentView.parentContainer === this);
         if (newContentView.parentContainer && newContentView.parentContainer !== this)
             return;

         var currentlyShowing = (this.currentContentView === oldContentView);
         if (currentlyShowing)
             this._hideContentView(oldContentView);

         // Disassociate with the old content view.
         this._disassociateFromContentView(oldContentView);

         // Associate with the new content view.
         newContentView._parentContainer = this;

         // Replace all occurrences of oldContentView with newContentView in the back/forward list.
         for (var i = 0; i < this._backForwardList.length; ++i) {
             if (this._backForwardList[i] === oldContentView)
                 this._backForwardList[i] = newContentView;
         }

         if (currentlyShowing) {
             this._showContentView(newContentView);
             this.dispatchEventToListeners(WebInspector.ContentViewContainer.Event.CurrentContentViewDidChange);
         }
     },

     closeAllContentViewsOfPrototype: function(constructor)
     {
         if (!this._backForwardList.length) {
             console.assert(this._currentIndex === -1);
             return;
         }

         // Do a check to see if all the content views are instances of this prototype.
         // If they all are we can use the quicker closeAllContentViews method.
         var allSamePrototype = true;
         for (var i = this._backForwardList.length - 1; i >= 0; --i) {
             if (!(this._backForwardList[i] instanceof constructor)) {
                 allSamePrototype = false;
                 break;
             }
         }

         if (allSamePrototype) {
             this.closeAllContentViews();
             return;
         }

         var oldCurrentContentView = this.currentContentView;

         // Hide and disassociate with all the content views that are instances of the constructor.
         for (var i = this._backForwardList.length - 1; i >= 0; --i) {
             var contentView = this._backForwardList[i];
             if (!(contentView instanceof constructor))
                 continue;

             if (contentView === oldCurrentContentView)
                 this._hideContentView(contentView);

             if (this._currentIndex >= i) {
                 // Decrement the currentIndex since we will remove an item in the back/forward array
                 // that it the current index or comes before it.
                 --this._currentIndex;
             }

             this._disassociateFromContentView(contentView);

             // Remove the item from the back/forward list.
             this._backForwardList.splice(i, 1);
         }

         var currentContentView = this.currentContentView;
         console.assert(currentContentView || (!currentContentView && this._currentIndex === -1));

         if (currentContentView && currentContentView !== oldCurrentContentView) {
             this._showContentView(currentContentView);
             this.dispatchEventToListeners(WebInspector.ContentViewContainer.Event.CurrentContentViewDidChange);
         }
     },

     closeAllContentViews: function()
     {
         if (!this._backForwardList.length) {
             console.assert(this._currentIndex === -1);
             return;
         }

         // Hide and disassociate with all the content views.
         for (var i = 0; i < this._backForwardList.length; ++i) {
             var contentView = this._backForwardList[i];
             if (i === this._currentIndex)
                 this._hideContentView(contentView);
             this._disassociateFromContentView(contentView);
         }

         this._backForwardList = [];
         this._currentIndex = -1;

         this.dispatchEventToListeners(WebInspector.ContentViewContainer.Event.CurrentContentViewDidChange);
     },

     canGoBack: function()
     {
         return this._currentIndex > 0;
     },

     canGoForward: function()
     {
         return this._currentIndex < this._backForwardList.length - 1;
     },

     goBack: function()
     {
         if (!this.canGoBack())
             return;
         this.showBackForwardEntry(this._currentIndex - 1);
     },

     goForward: function()
     {
         if (!this.canGoForward())
             return;
         this.showBackForwardEntry(this._currentIndex + 1);
     },

     shown: function()
     {
         var currentContentView = this.currentContentView;
         if (!currentContentView)
             return;

         this._showContentView(currentContentView);
     },

     hidden: function()
     {
         var currentContentView = this.currentContentView;
         if (!currentContentView)
             return;

         this._hideContentView(currentContentView);
     },

     // Private

     _addContentViewElement: function(contentView)
     {
         if (contentView.element.parentNode !== this._element)
             this._element.appendChild(contentView.element);
     },

     _removeContentViewElement: function(contentView)
     {
         if (contentView.element.parentNode)
             contentView.element.parentNode.removeChild(contentView.element);
     },

     _disassociateFromContentView: function(contentView)
     {
         console.assert(!contentView.visible);

         contentView._parentContainer = null;

         var representedObject = contentView.representedObject;
         if (!representedObject || !representedObject.__contentViews)
             return;

         representedObject.__contentViews.remove(contentView);

         contentView.closed();
     },

     _saveScrollPositionsForContentView: function(contentView)
     {
         var scrollableElements = contentView.scrollableElements || [];
         for (var i = 0; i < scrollableElements.length; ++i) {
             var element = scrollableElements[i];
             if (!element)
                 continue;
             if (contentView.shouldKeepElementsScrolledToBottom)
                 element._savedIsScrolledToBottom = element.isScrolledToBottom();
             element._savedScrollTop = element.scrollTop;
             element._savedScrollLeft = element.scrollLeft;
         }
     },

     _restoreScrollPositionsForContentView: function(contentView)
     {
         var scrollableElements = contentView.scrollableElements || [];
         for (var i = 0; i < scrollableElements.length; ++i) {
             var element = scrollableElements[i];
             if (!element)
                 continue;

             // Restore the top scroll position by either scrolling to the bottom or to the saved position.
             element.scrollTop = element._savedIsScrolledToBottom ? element.scrollHeight : element._savedScrollTop;

             // Don't restore the left scroll position when scrolled to the bottom. This way the when content changes
             // the user won't be left in a weird horizontal position.
             element.scrollLeft = element._savedIsScrolledToBottom ? 0 : element._savedScrollLeft;
         }
     },

     _showContentView: function(contentView)
     {
         if (contentView.visible)
             return;

         this._addContentViewElement(contentView);

         this._prepareContentViewToShow(contentView);
     },

     _prepareContentViewToShow: function(contentView)
     {
         this._restoreScrollPositionsForContentView(contentView);

         contentView.visible = true;
         contentView.shown();
         contentView.updateLayout();
     },

     _hideContentView: function(contentView)
     {
         if (!contentView.visible)
             return;

         this._prepareContentViewToHide(contentView);

         this._removeContentViewElement(contentView);
     },

     _prepareContentViewToHide: function(contentView)
     {
         contentView.visible = false;
         contentView.hidden();

         this._saveScrollPositionsForContentView(contentView);
     }
 };

 WebInspector.ContentViewContainer.prototype.__proto__ = WebInspector.Object.prototype;
	/*
	* Copyright (C) 2013 Apple 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.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
	* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
	* THE POSSIBILITY OF SUCH DAMAGE.
	*/

	WebInspector.ContentViewContainer = function(element)
	{
	WebInspector.Object.call(this);

	this._element = element \|\| document.createElement("div");
	this._element.classList.add(WebInspector.ContentViewContainer.StyleClassName);

	this._backForwardList = [];
	this._currentIndex = -1;
	};

	WebInspector.ContentViewContainer.StyleClassName = "content-view-container";

	WebInspector.ContentViewContainer.Event = {
	CurrentContentViewDidChange: "content-view-container-current-content-view-did-change"
	};

	WebInspector.ContentViewContainer.prototype = {
	constructor: WebInspector.ContentViewContainer,

	// Public

	get element()
	{
	return this._element;
	},

	get currentIndex()
	{
	return this._currentIndex;
	},

	get backForwardList()
	{
	return this._backForwardList;
	},

	get currentContentView()
	{
	if (this._currentIndex < 0 \|\| this._currentIndex > this._backForwardList.length - 1)
	return null;
	return this._backForwardList[this._currentIndex];
	},

	updateLayout: function()
	{
	var currentContentView = this.currentContentView;
	if (currentContentView)
	currentContentView.updateLayout();
	},

	contentViewForRepresentedObject: function(representedObject, onlyExisting)
	{
	console.assert(representedObject);
	if (!representedObject)
	return null;

	// Iterate over all the known content views for the representedObject (if any) and find one that doesn't
	// have a parent container or has this container as its parent.
	var contentView = null;
	for (var i = 0; representedObject.__contentViews && i < representedObject.__contentViews.length; ++i) {
	var currentContentView = representedObject.__contentViews[i];
	if (!currentContentView._parentContainer \|\| currentContentView._parentContainer === this) {
	contentView = currentContentView;
	break;
	}
	}

	console.assert(!contentView \|\| contentView instanceof WebInspector.ContentView);
	if (contentView instanceof WebInspector.ContentView)
	return contentView;

	// Return early to avoid creating a new content view when onlyExisting is true.
	if (onlyExisting)
	return null;

	try {
	// No existing content view found, make a new one.
	contentView = new WebInspector.ContentView(representedObject);
	} catch (e) {
	console.error(e);
	return null;
	}

	// Remember this content view for future calls.
	if (!representedObject.__contentViews)
	representedObject.__contentViews = [];
	representedObject.__contentViews.push(contentView);

	return contentView;
	},

	showContentViewForRepresentedObject: function(representedObject)
	{
	var contentView = this.contentViewForRepresentedObject(representedObject);
	if (!contentView)
	return null;

	this.showContentView(contentView);

	return contentView;
	},

	showContentView: function(contentView)
	{
	console.assert(contentView instanceof WebInspector.ContentView);
	if (!(contentView instanceof WebInspector.ContentView))
	return null;

	// Don't allow showing a content view that is already associated with another container.
	// Showing a content view that is already associated with this container is allowed.
	console.assert(!contentView.parentContainer \|\| contentView.parentContainer === this);
	if (contentView.parentContainer && contentView.parentContainer !== this)
	return null;

	// Don't do anything if the content view is already the current content view.
	var currentContentView = this.currentContentView;
	if (currentContentView === contentView)
	return contentView;

	// Showing a content view will truncate the back/forward list after the current index and insert the content view
	// at the end of the list. Finally, the current index will be updated to point to the end of the back/forward list.

	// Increment the current index to where we will insert the content view.
	var newIndex = this._currentIndex + 1;

	// Insert the content view at the new index. This will remove any content views greater than or equal to the index.
	var removedItems = this._backForwardList.splice(newIndex, this._backForwardList.length - newIndex, contentView);

	console.assert(newIndex === this._backForwardList.length - 1);
	console.assert(this._backForwardList[newIndex] === contentView);

	// Disassociate with the removed content views.
	for (var i = 0; i < removedItems.length; ++i) {
	// Skip disassociation if this content view is still in the back/forward list.
	if (this._backForwardList.contains(contentView))
	continue;

	this._disassociateFromContentView(removedItems[i]);
	}

	// Associate with the new content view.
	contentView._parentContainer = this;

	this.showBackForwardEntry(newIndex);

	return contentView;
	},

	showBackForwardEntry: function(index)
	{
	console.assert(index >= 0 && index <= this._backForwardList.length - 1);
	if (index < 0 \|\| index > this._backForwardList.length - 1)
	return;

	if (this._currentIndex === index)
	return;

	// Hide the currently visible content view.
	var currentContentView = this.currentContentView;
	if (currentContentView)
	this._hideContentView(currentContentView);

	this._currentIndex = index;

	this._showContentView(this.currentContentView);

	this.dispatchEventToListeners(WebInspector.ContentViewContainer.Event.CurrentContentViewDidChange);
	},

	replaceContentView: function(oldContentView, newContentView)
	{
	console.assert(oldContentView instanceof WebInspector.ContentView);
	if (!(oldContentView instanceof WebInspector.ContentView))
	return;

	console.assert(newContentView instanceof WebInspector.ContentView);
	if (!(newContentView instanceof WebInspector.ContentView))
	return;

	console.assert(oldContentView.parentContainer === this);
	if (oldContentView.parentContainer !== this)
	return;

	console.assert(!newContentView.parentContainer \|\| newContentView.parentContainer === this);
	if (newContentView.parentContainer && newContentView.parentContainer !== this)
	return;

	var currentlyShowing = (this.currentContentView === oldContentView);
	if (currentlyShowing)
	this._hideContentView(oldContentView);

	// Disassociate with the old content view.
	this._disassociateFromContentView(oldContentView);

	// Associate with the new content view.
	newContentView._parentContainer = this;

	// Replace all occurrences of oldContentView with newContentView in the back/forward list.
	for (var i = 0; i < this._backForwardList.length; ++i) {
	if (this._backForwardList[i] === oldContentView)
	this._backForwardList[i] = newContentView;
	}

	if (currentlyShowing) {
	this._showContentView(newContentView);
	this.dispatchEventToListeners(WebInspector.ContentViewContainer.Event.CurrentContentViewDidChange);
	}
	},

	closeAllContentViewsOfPrototype: function(constructor)
	{
	if (!this._backForwardList.length) {
	console.assert(this._currentIndex === -1);
	return;
	}

	// Do a check to see if all the content views are instances of this prototype.
	// If they all are we can use the quicker closeAllContentViews method.
	var allSamePrototype = true;
	for (var i = this._backForwardList.length - 1; i >= 0; --i) {
	if (!(this._backForwardList[i] instanceof constructor)) {
	allSamePrototype = false;
	break;
	}
	}

	if (allSamePrototype) {
	this.closeAllContentViews();
	return;
	}

	var oldCurrentContentView = this.currentContentView;

	// Hide and disassociate with all the content views that are instances of the constructor.
	for (var i = this._backForwardList.length - 1; i >= 0; --i) {
	var contentView = this._backForwardList[i];
	if (!(contentView instanceof constructor))
	continue;

	if (contentView === oldCurrentContentView)
	this._hideContentView(contentView);

	if (this._currentIndex >= i) {
	// Decrement the currentIndex since we will remove an item in the back/forward array
	// that it the current index or comes before it.
	--this._currentIndex;
	}

	this._disassociateFromContentView(contentView);

	// Remove the item from the back/forward list.
	this._backForwardList.splice(i, 1);
	}

	var currentContentView = this.currentContentView;
	console.assert(currentContentView \|\| (!currentContentView && this._currentIndex === -1));

	if (currentContentView && currentContentView !== oldCurrentContentView) {
	this._showContentView(currentContentView);
	this.dispatchEventToListeners(WebInspector.ContentViewContainer.Event.CurrentContentViewDidChange);
	}
	},

	closeAllContentViews: function()
	{
	if (!this._backForwardList.length) {
	console.assert(this._currentIndex === -1);
	return;
	}

	// Hide and disassociate with all the content views.
	for (var i = 0; i < this._backForwardList.length; ++i) {
	var contentView = this._backForwardList[i];
	if (i === this._currentIndex)
	this._hideContentView(contentView);
	this._disassociateFromContentView(contentView);
	}

	this._backForwardList = [];
	this._currentIndex = -1;

	this.dispatchEventToListeners(WebInspector.ContentViewContainer.Event.CurrentContentViewDidChange);
	},

	canGoBack: function()
	{
	return this._currentIndex > 0;
	},

	canGoForward: function()
	{
	return this._currentIndex < this._backForwardList.length - 1;
	},

	goBack: function()
	{
	if (!this.canGoBack())
	return;
	this.showBackForwardEntry(this._currentIndex - 1);
	},

	goForward: function()
	{
	if (!this.canGoForward())
	return;
	this.showBackForwardEntry(this._currentIndex + 1);
	},

	shown: function()
	{
	var currentContentView = this.currentContentView;
	if (!currentContentView)
	return;

	this._showContentView(currentContentView);
	},

	hidden: function()
	{
	var currentContentView = this.currentContentView;
	if (!currentContentView)
	return;

	this._hideContentView(currentContentView);
	},

	// Private

	_addContentViewElement: function(contentView)
	{
	if (contentView.element.parentNode !== this._element)
	this._element.appendChild(contentView.element);
	},

	_removeContentViewElement: function(contentView)
	{
	if (contentView.element.parentNode)
	contentView.element.parentNode.removeChild(contentView.element);
	},

	_disassociateFromContentView: function(contentView)
	{
	console.assert(!contentView.visible);

	contentView._parentContainer = null;

	var representedObject = contentView.representedObject;
	if (!representedObject \|\| !representedObject.__contentViews)
	return;

	representedObject.__contentViews.remove(contentView);

	contentView.closed();
	},

	_saveScrollPositionsForContentView: function(contentView)
	{
	var scrollableElements = contentView.scrollableElements \|\| [];
	for (var i = 0; i < scrollableElements.length; ++i) {
	var element = scrollableElements[i];
	if (!element)
	continue;
	if (contentView.shouldKeepElementsScrolledToBottom)
	element._savedIsScrolledToBottom = element.isScrolledToBottom();
	element._savedScrollTop = element.scrollTop;
	element._savedScrollLeft = element.scrollLeft;
	}
	},

	_restoreScrollPositionsForContentView: function(contentView)
	{
	var scrollableElements = contentView.scrollableElements \|\| [];
	for (var i = 0; i < scrollableElements.length; ++i) {
	var element = scrollableElements[i];
	if (!element)
	continue;

	// Restore the top scroll position by either scrolling to the bottom or to the saved position.
	element.scrollTop = element._savedIsScrolledToBottom ? element.scrollHeight : element._savedScrollTop;

	// Don't restore the left scroll position when scrolled to the bottom. This way the when content changes
	// the user won't be left in a weird horizontal position.
	element.scrollLeft = element._savedIsScrolledToBottom ? 0 : element._savedScrollLeft;
	}
	},

	_showContentView: function(contentView)
	{
	if (contentView.visible)
	return;

	this._addContentViewElement(contentView);

	this._prepareContentViewToShow(contentView);
	},

	_prepareContentViewToShow: function(contentView)
	{
	this._restoreScrollPositionsForContentView(contentView);

	contentView.visible = true;
	contentView.shown();
	contentView.updateLayout();
	},

	_hideContentView: function(contentView)
	{
	if (!contentView.visible)
	return;

	this._prepareContentViewToHide(contentView);

	this._removeContentViewElement(contentView);
	},

	_prepareContentViewToHide: function(contentView)
	{
	contentView.visible = false;
	contentView.hidden();

	this._saveScrollPositionsForContentView(contentView);
	}
	};

	WebInspector.ContentViewContainer.prototype.__proto__ = WebInspector.Object.prototype;