cefsharp/cefsharp

.NET (WPF and Windows Forms) bindings for the Chromium Embedded Framework

Got a quick question? Discussions here on GitHub is the preferred place to ask!

CefSharp lets you embed Chromium in .NET apps. It is a lightweight .NET wrapper around the Chromium Embedded Framework (CEF) by Marshall A. Greenblatt. About 30% of the bindings are written in C++/CLI with the majority of code here is C#. It can be used from C# or VB, or any other CLR language. CefSharp provides both WPF and WinForms web browser control implementations.

CefSharp is BSD licensed, so it can be used in both proprietary and free/open source applications. For the full details, see the LICENSE file.

If you like and use CefSharp please consider signing up for a small monthly donation, even $25 can help tremendously. See Financial Support for more details.

Releases

Stable binaries are released on NuGet, and contain everything you need to embed Chromium in your .Net/CLR application. For usage see the Quick Start guide or checkout CefSharp.MinimalExample project for basic demos using the CefSharp NuGet packages.

• CefSharp.WinForms
• CefSharp.Wpf
• CefSharp.OffScreen
• CefSharp.Wpf.HwndHost (A HwndHost based WPF implementation, similar to hosting the WinForms version in WPF, supports data binding, airspace issues apply).

Documentation

• See the CefSharp.Wpf.Example or CefSharp.WinForms.Example projects for example web browsers built with CefSharp. They demo most of the available features.
• See the CefSharp.MinimalExample project for a basic demo of using the CefSharp NuGet packages.
• See the General Usage Guide in help getting started/dealing with common scenarios.
• See the Wiki for work-in-progress documentation
• See the FAQ for help with common issues
• Upgrading from an earlier version of CefSharp? See the ChangeLog for breaking changes and upgrade tips.
• CefSharp API generated from the source code comments.

Contact

Please keep the Issue Tracker for Bugs only please! Before submitting a PR please read CONTRIBUTING.

• CefSharp Discussions is generally where CefSharp specific questions should be asked, please search before posting, thanks!
• Stackoverflow is where generic html/javascript/C# questions can be asked.
• Chromium Embedded Framework(CEF) Forum

Branches & Forks

This is the official CefSharp fork, as maintained by the CefSharp community. You can also view the entire network of public forks/branches.

Development is done in the master branch. New features are preferably added in feature branches, if the changes are more than trivial. New PR's should be targeted against master.

When a new release is imminent a release branch is created. We try to avoid making public facing API changes in release branches (Adding new features is fine, just not breaking changes).

Releases

CI Builds
Every commit on master produces a Nuget package. Use at your own risk!

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Pre-release

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Stable

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Release Branches

With each release a new branch is created, for example the 92.0.260 release corresponds to the cefsharp/92 branch. If you're new to CefSharp and are downloading the source to check it out, please use a Release branch.

* VC++ 2019 is required starting with version 93
** For .Net Core Packages .Net Core 3.1 or .Net 5/6/7 are required.

Branch	CEF Version	VC++ Version	.Net Version	Status
master	6099	2019*	4.6.2**	Development
cefsharp/120	6099	2019*	4.6.2**	Release
cefsharp/119	6045	2019*	4.6.2**	Unsupported
cefsharp/118	5993	2019*	4.6.2**	Unsupported
cefsharp/117	5938	2019*	4.6.2**	Unsupported
cefsharp/116	5845	2019*	4.6.2**	Unsupported
cefsharp/115	5790	2019*	4.6.2**	Unsupported
cefsharp/114	5735	2019*	4.5.2**	Unsupported
cefsharp/113	5615	2019*	4.5.2**	Unsupported
cefsharp/112	5615	2019*	4.5.2**	Unsupported
cefsharp/111	5563	2019*	4.5.2**	Unsupported
cefsharp/110	5481	2019*	4.5.2**	Unsupported
cefsharp/109	5414	2019*	4.5.2**	Unsupported
cefsharp/108	5359	2019*	4.5.2**	Unsupported
cefsharp/107	5304	2019*	4.5.2**	Unsupported
cefsharp/106	5249	2019*	4.5.2**	Unsupported
cefsharp/105	5195	2019*	4.5.2**	Unsupported
cefsharp/104	5112	2019*	4.5.2**	Unsupported
cefsharp/103	5060	2019*	4.5.2**	Unsupported
cefsharp/102	5005	2019*	4.5.2**	Unsupported
cefsharp/101	4951	2019*	4.5.2**	Unsupported
cefsharp/100	4896	2019*	4.5.2**	Unsupported
cefsharp/99	4844	2019*	4.5.2**	Unsupported
cefsharp/98	4758	2019*	4.5.2**	Unsupported
cefsharp/97	4692	2019*	4.5.2**	Unsupported
cefsharp/96	4664	2019*	4.5.2**	Unsupported
cefsharp/95	4638	2019*	4.5.2**	Unsupported
cefsharp/94	4606	2019*	4.5.2**	Unsupported
cefsharp/93	4577	2019*	4.5.2**	Unsupported
cefsharp/92	4515	2015*	4.5.2**	Unsupported
cefsharp/91	4472	2015*	4.5.2**	Unsupported
cefsharp/90	4430	2015*	4.5.2**	Unsupported
cefsharp/89	4389	2015*	4.5.2**	Unsupported
cefsharp/88	4324	2015*	4.5.2**	Unsupported
cefsharp/87	4280	2015*	4.5.2**	Unsupported
cefsharp/86	4240	2015	4.5.2	Unsupported
cefsharp/85	4183	2015	4.5.2	Unsupported
cefsharp/84	4147	2015	4.5.2	Unsupported
cefsharp/83	4103	2015	4.5.2	Unsupported
cefsharp/81	4044	2015	4.5.2	Unsupported
cefsharp/79	3945	2015	4.5.2	Unsupported
cefsharp/77	3865	2015	4.5.2	Unsupported
cefsharp/75	3770	2015	4.5.2	Unsupported
cefsharp/73	3683	2015	4.5.2	Unsupported
cefsharp/71	3578	2015	4.5.2	Unsupported
cefsharp/69	3497	2015	4.5.2	Unsupported
cefsharp/67	3396	2015	4.5.2	Unsupported
cefsharp/65	3325	2015	4.5.2	Unsupported
cefsharp/63	3239	2013	4.5.2	Unsupported
cefsharp/62	3202	2013	4.5.2	Unsupported
cefsharp/57	2987	2013	4.5.2	Unsupported
cefsharp/55	2883	2013	4.5.2	Unsupported
cefsharp/53	2785	2013	4.5.2	Unsupported
cefsharp/51	2704	2013	4.5.2	Unsupported
cefsharp/49	2623	2013	4.0	Unsupported
cefsharp/47	2526	2013	4.0	Unsupported
cefsharp/45	2454	2013	4.0	Unsupported
cefsharp/43	2357	2012	4.0	Unsupported
cefsharp/41	2272	2012	4.0	Unsupported
cefsharp/39	2171	2012	4.0	Unsupported
cefsharp/37	2062	2012	4.0	Unsupported

* VC++ 2019 is required starting with version 93
** For .Net Core Packages .Net Core 3.1/.Net 5.0 is required.

Financial Support

Is your company making money thanks to CefSharp? Do you rely on regular updates to the project? Alex Maitland needs your support! Signup to GitHub Sponsors.

One-Time or Recurring contributions can be made through GitHub Sponsors it only takes a GitHub account and a credit card. You can also make a One-Time contribution via PayPal.

As a stay at home dad I (@amaitland) rely on your contributions to help support my family.

Links

• CefGlue: An alternative .NET CEF wrapper built using P/Invoke.
• CEF GitHub Project : The official CEF issue tracker
• CEF Forum : The official CEF Forum
• CEF API Docs : Well worth a read if you are implementing a new feature
• CefSharp API Doc

Projects using CefSharp

• HtmlView : Visual Studio extension bringing CefSharp for showing HTML pages inside VS.
• SharpBrowser : The fastest web browser for C# with tabbed browsing and HTML5/CSS3.
• Chromely CefSharp : Build HTML Desktop Apps on .NET/.NET Core 3/.NET 5 using native GUI, HTML5/CSS.

cefsharp's Issues

Context Menu, Inspect Element, Web Inspector

Is it possible to display the WebKit Web Inspector for debugging the DOM and JavaScript? In Chrome it's displayed from "Inspect element" on the context menu.

I don't see any context menu in CefWebBrowser. I don't see anything in the API for context menus, web inspector or developer tools.

If this isn't possible is there another way to debug the HTML and JavaScript?

Thanks for any help, and congratulations on a promising project!

Be friendly in runtime - UserControl vs Control

BrowserControl can be derived from Control, not from UserControl (simply replace UserControl to Control in sources).
UserControl doesn't do anything useful, but can have some negative effects.

CefSharp references System.Core.Dll

CefSharp references System.Core.Dll which is a .NET 3.5 assembly and as far as I can tell is no longer required. Can this be removed from the project? Unfortunately I don't have access to VS2008 and I can't get it to compile on VS2010.

Problem with .Net4 ,app.config solution not working

i am getting this

    "System.IO.FileNotFoundException was unhandled
      Message=Could not load file or assembly 'CefSharp.dll' or one of its                     
      dependencies."

i followed a solution from the website

  <?xml version="1.0"?>
         <configuration>
            <startup useLegacyV2RuntimeActivationPolicy="true"> 
            <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
      </startup>
  </configuration>

Yes i am building with.net 4

Http Post to URL?

Hey all,

It doesn't appear to yet be possible to do something like:

String postdata = "u=idcode";
System.Text.Encoding a = System.Text.Encoding.UTF8;
byte[] byte1 = a.GetBytes(postdata);
cefSharpBrowser.Load("anysite.php", "_SELF",byte1, "Content-Type: application/x-www-form-urlencoded" );

To post data to a form on a webpage... or am I just overlooking it?

Pointers?

Thanks,

Michael

CEF.Shutdown gives unexpected result: debug assertion or infinite lock!

Now call to CEF.Shutdown gives unexpected result: debug assertion or infinite lock.
Not usable at this moment...
I think, it is CEF-related, not CefSharp-related bug.

HTML5 Canvas pages cause crash

I'm experiencing an issue using CefSharp.Example when visiting pages that include canvas scripts such as rgraph.net and thejit.org on Windows XP Pro SP2.

The event log shows ".NET Runtime 2.0 Error" but I also have .NET 3.5 SP1 installed on this machine.

These pages work fine in Windows 7. Am I missing a requirement?

CEF.Initialize fails

Hi,

I have downloaded the cefsharp version - https://github.com/ataranto/CefSharp/tree/cef_update branch and cef_binary_1.963.439_windows.
the cefsharp solution is compiling fine , but when I try to run the cefSharp.Example project,
the program execution fails(returning false) at "CEF.Initialize" in program.cs.

When I use cefsharp master version with cef_binary_1.963.439_windows, AccessViolationException
(Attempted to read or write protected memory. This is often an indication that other memory is corrupt.)
thrown at Initialize method.

Using cefsharp V0.3.1 & cef_binary_r149 works successfully for me. No CEF.Initialize error.

I am using VS2008. Am I using the correct version of cef binaries?
Please help me in fixing this error.

Thanks

Unable to "tab" through WPF browser controls

pressing the TAB key while focusing on the browser should tab between the different controls within the browser, but on WPF it seems to bypass them. I imagine it has something to do with the Frame it's contained in.

Assembly 'CefSharp' does not have a strong name

Assembly CefSharp is not usable, 'cause is not signed...
I need binary package with signed assembly! :)

Windows Auth

Hello.
I'm on a project about web app on PC.
I needed to use HTML5 and I found Cef.
Thanks to you all the work you've done.

And now I'm having a trouble with windows auth.
I needed to use another site's resources that uses Windows Auth.
so, I've been looking around but I couldn't find anywhere.

Is there someone got the same trouble? and solved?
Or any clue to solve?

plz Help Me Out~~!

I'm gonna die......

ProgressChanged event required

ProgressChanged event required...

Update?

not sure if you are planning to update so are you?

Update to CEF to latest revision. 158 -> 187+

CefSharp should be updated to incorporate all of the improvements made to CEF since revision 158

Be friendly in runtime - doesn't sized properly unless control is not resized from external code.

After control created (with fill docking) - it's not sized properly unless form is not beign resized.
It looks like while control creating - it use default sizes, then setting it to be docked + changing parent - doesn't generate onsizechanged, - may be control doesn't handle something important.

noob question

ihave built cefsharp browser before once, but now all that code is missing idk why.
i started all over, i used to use this but now it doesn't work

CefSharp.CefWebBrowser webbrowser = new CefSharp.CefWebBrowser();
        webbrowser.Dock = DockStyle.Fill;
        webbrowser.Load("http://www.google.com");
        webbrowser.CreateControl();
        this.Controls.Add(webbrowser);

Rightclick on webpages

Hi,
Why I can right click on webpages when using CefSharp browser?

by using cefsharp how to get the browser page source

HI,

how can i use the cefsharp browser to get the page source. I mean i would like to use cefsharp just like a form filling page programmatically , by using cefsharp browser by programmatically i want to fill some content with in the site it displays, can i perform a click on a button of the browser by programmatically.

Poor rendering performance

The rendering performance on for instance google maps is extremely poor compared to Chrome 8.

Any ideas why and how to fix it?

Great project by the way :-)

Bound JS Sub Class Objects

I am trying to bind an object to CEF using cefsharp. I am able to bind a single class, such as class NativeObject to the Native JS object. I would like to be able to bind sub classes and create functions inside another class for different operations and have Native be the parent for all, such as: Native.window.resize.

Create Javascript object in browser window

There should be a way to create a Javascript object (like CefSharp.CEF.RegisterJsObject) but in the browser window (CefSharp.CefWebBrowser). I have an application that has two browser windows (meaning two CefSharp.CefWebBrowser controls) and I need to register the same Javascript object in both.
To my knowledge, this is possible in CEF but I don't know how to do it in CefSharp.

Building

Hi

My company has a pre-existing solution that utilises CefSharp. The person who wrote this solution has left the company. I've obtained the source code for this but it's not working. I just get an error "The specified module could not be found". To solve this I downloaded your copy of CefSharp and tried to run the CefSharp.Example project. I get the same issue.

I runing windows 7 x64. I've got Chrome 17.0.963.56. I've not downloaded and built Chromium because I was under the impression that this should "work out of the box" without this.

what am I missing? Sorry to be vague but I'm fast running out of ideas and any help would be greatly appreciated!

Regards

Liam

RunScript: a script that runs cleanly but returns a null value causes an exception

The v8task.v2.patch calls jsTask->HandleError() if result.IsEmpty() is true, raising a ScriptException. Calling someJavaScriptMethodThatReturnsNull() shouldn't raise an exception.

I'd like to just have CefWebBrowser.RunScript() return null if result.IsEmpty() is true.

CEFSharp v0.3.1 unnecessarily includes System.Core breaking .NET 2.0 compatability

CEFSharp being a wrapper project, compatability might be important. Since System.Core can just be removed from CEFSharp I figured it might be worth making an issue to remind that it should be removed so that others don't need to recompile each released binary.

While it's understandable to not want to be locked into .NET 2.0, I hope any shifts to a higher framework version are a last resort. :) Either way, the project is a nice contribution and I'm sure it will be used by many. Thanks

CefSharp.CefWebBrowser RunScript return type

Currently, the method RunScript (in CefSharp.CefWebBrowser) always returns a string when it should return 'object', boxing the correct type returned by the script. I know that the conversion can be made after the call to RunScript but the underlying type is lost. Although I can convert the string "true" to boolean true, I don't know if the function wanted to return a string or a boolean.

CefWebBrowser display dependent

I have a UserControl that has an instance of CefWebBrowser (it occupies it's entire area). When my program starts, it creates several instances of my UserControl, but only one is initially shown (the primary one). The others are swapped for the primary UserControl in turn so that only one control is displayed at any given time. When each UserControl is created, it calls CefWebBrowser.Load but I noticed that nothing actually happens until the UserControl, where the CefWebBrowser is attached to, gets displayed. In fact, if I call CefWebBrowser.RunScript after CefWebBrowser.Load (even giving it time to load the page), it freezes completely.

Does it run with dotnet 2.0

I mean the dependency with system.core is mandatory?

AppDomain support

Currently, trying to use CefWebBrowser from any AppDomain other than the primary/default AppDomain results in:

System.ArgumentException {"Cannot pass a GCHandle across AppDomains.\r\nParameter name: handle"}
at System.Runtime.InteropServices.GCHandle.InternalCheckDomain(IntPtr handle)
at System.Runtime.InteropServices.GCHandle.FromIntPtr(IntPtr value)
at System.Runtime.InteropServices.GCHandle.op_Explicit(IntPtr value)
at gcroot<CefSharp::CefWebBrowser ^>.->(gcroot<CefSharp::CefWebBrowser ^>* )
at CefSharp.HandlerAdapter.HandleAfterCreated(HandlerAdapter* , CefRefPtr* browser)

Now, I'm no expert at this stuff. The project where I'm trying to use CefSharp is also the first project I've built that used AppDomains. But, from what I can find on this online, the problem seems to be that the native side of CefSharp always calls into the managed side using the default AppDomain, regardless of the caller's AppDomain.

Building with /clr:initialappdomain is a quick fix, at least for my situation, where only one of my AppDomains needs to use CefSharp. "Properly" supporting AppDomains probably wouldn't be so easy however. I recommend at least adding this switch to the "additional commandline options" page, and documenting that CefSharp should only be loaded in one AppDomain at a time.

handle file download

Hi,

How can I implement the necessary code to handle file downloads? I can see there's a "HandleBeforeResourceLoad" method, but I don't know what to do with it...

Thanks

Building Solution

Hi, I am trying to build CEF solution in VS2010, but when I build CefSharp project, I got theese errors:

Error 4 error C2371: 'char16_t' : redefinition; different basic types c:_dev\cefsharp\include\cef_string_types.h 49 1 CefSharp
Error 6 error C2664: 'cef_string_utf16_set' : cannot convert parameter 1 from 'const wchar_t *' to 'const char16_t *' c:_dev\cefsharp\include\cef_string_wrappers.h 245 1 CefSharp
Error 5 error C2665: 'std::basic_string<_Elem,_Traits,_Ax>::basic_string' : none of the 15 overloads could convert all the argument types c:_dev\cefsharp\include\cef_string_wrappers.h 241 1 CefSharp

Can anyone help me, what is missing ?

OverflowException in BindingHandler::Execute

v0.3: When running binding test we get an exception on the following line of BindingHandler:

    array<System::Object^>^ suppliedArguments = gcnew array<Object^>(arguments.size());

    System.OverflowException was unhandled
    Message: Arithmetic operation resulted in an overflow.

Be friendly in runtime - creation of control without CEF.Initialize

Creation of control without CEF.Initialize must do one of this:

1. generate exception
2. implicity call CEF.Initialize.

Without CEF.Initialize control in any case is not usable.

Be friendly in runtime - NullReferenceException

Current control in many situations can generate some exceptions (NullReferenceException for ex.) - it's bad. We need adds some checks and generate own exception type, or InvalidOperationException with description.

Mouse not working with google maps api v3

No mouse panning og zooming (appart from wheel) when using sites with google maps api v3.

Example:
http://code.google.com/apis/maps/articles/mvcfun/twittersearch.html

Error Shutdown Program

Hello,

using newest Version from you with VB.NET ... Everything perfectly, but

Closing my Program getting the following Error:

Title:

.NET-BroadcastEventWindow.2.0.0.0.378734a.0: MyCefSharp.exe - Fehler in Anwendung

Die Anweisung in "0x00000000" verweist auf Speicher in "0x0000000". Der Vorgang "read" konnte nicht auf dem Speicher durchgeführt werden.

Klicken Sie auf OK um das Programm zu beenden.

I am not perfect in translating, but in english i guess it means:

The statement in ... refers to memory in... The process "read" could not be done in Memory ..

Thanks for every helping

Thomas

(Sorry for bad english....)

Ready event needed

While control initializes asynchroniously, we may be needed in Ready event (HandleAfterCreated), to say that browser is actually ready.
Or may be better wait for browser becames ready or throw user-friendly messages in dependend methods. Now Load method throw NullReferenceException, if it is executed before internal CEF loop executed HandleAfterCreated.

Be friendly in runtime. - event invocation

Event generation require Control.Invoke (imho, better with BeginInvoke). This allow write more simply event handlers.
Only one problem - Control.IsInvokeRequired can lie, so don't forget, that IsInvokeRequired always lie while IsHandleCreated==false, and have more rare cases what it's also lies. Only one safe check can be performed - check actually thread to equality to thread that created control. (But all techniques requires some tests).

Pure virtual function call C++ runtime error

Been getting the following error when executing some JavaScript with the WPF browser.

The Microsoft description of the error is here:

http://support.microsoft.com/kb/125749

I've so far not been able to reliably reproduce it, unfortunately.

Add support to window.external

This is a must have function in the stock .net Webbrowser control, allowing the javascript to communicate with the host app.

Unlikely, I'm unable to see if this is a CEF code side, or if this can be handled by CefSharp.
I find this topic, but I'm unable to understand it...
http://magpcss.org/ceforum/viewtopic.php?f=6&t=187

copy,paste,cut

copy,paste,cut,select all
any way to get these working

2 newbie questions

Hello,
I'm new to CefSharp, and so far it's been working great.
I was able to build it with .NET 2 and it works pretty good

1. question is with regard to persistent cookies:
   For example: If I open Facebook or Netflix I have to log in, and after checking "Keep me logged in", in regular browser I don't need to log in again on browser reopening, with CefSharp I get prompted to log in again.
   As I see CEF version used in chillitom tree does not have Persistent Cookies, but newer branches like ataranto tree has it.
   How do you make CefSharp use PersistentCookies?

2.question
How do I turn off logging?

Thanks for your answers.

Mysterious of CEF.Initialize

"I don't understand why i got browser uninitialized, when i call in OnLoad method and CEF.Initialize, then create control - looks like CEF loop dosn't executed immediately..."

Mysterious of CEF.Initialize - it's look like multithreaded CEF loop creates after some UI message loops processed, - Application.DoEvents() solves this my question. Strange effects can be reached - it's looks like not CefSharp issue, but need tests/checks or handle this situation if possible.

Compilation troubles with cef_binary_r149_VS2005-VS2008 in Debug/Release

Now CefSharp easy can be compiled in MSVS2008 in Debug mode.

How compile in release?

Also i can't compile with any of cef_binary_r149_VS2005-VS2008\lib\Debug or Release, 2005 or 2008 libraries. What libraries placed in CefSharp\libs directory?

custom error page

any ideas about making a custom error page

KeyDown/KeyPress Events

When will this events be implemented?
I only find this definition:

virtual RetVal HandleKeyEvent(CefRefPtr browser, KeyEventType type, int code, int modifiers, bool isSystemKey) =0;

cef.h

and this plug:

virtual RetVal HandleKeyEvent(CefRefPtr browser, KeyEventType type, int code, int modifiers, bool isSystemKey) { return RV_CONTINUE; }

HandlerAdapter.h

But I don't find implementation which I can use for implement shortcuts in my browser.

Usability of BrowserControl: Naming conventions

Text below - this is all of my personal imho...

For first, naming of control, may be better will be CefWebBrowser, like:

1. WebBrowser (System.Windows.Forms).
2. GeckoWebBrowser (GeckoFX).

API of this control will be must be maximum as possible be similar to WebBrowser, but:

• Only if API of CefWebBrowser control is not contradiction to CEF namings and ideology.
• Only if it is possible.

For example:
Load(url) - WebBrowser.Navigate(url)

Events:
LoadEnd - Navigated

But on other side: while CEF have methods Load and LoadBegin/LoadEnd events - CefSharp must use this names - it's looks as better solution.

Of course we can create aliases: Navigate and Load methods, but i think that this is a bad idea.

It can be good idea only if your positioning CefSharp as simply replacement for WebBrowser for simply cases (without DOM access). DOM access - is unique for every browser, so no bonuses we can reach.
Replacement wrapper in any cases can be simply written... it's another topic.

MSVS2010 and .NET 4 (Client Profile) support required.

I know that it's a lot of works - but now we have natural lib-hell even while using msvs2008...

And may be i wrong - .lib files looks as libraries that use static-linking of msvcrt.

PS: For what purposes used libcef_dll_wrapper and libcef? Why not only one of them?

Unable to scroll select tag options

I have a select field with lots of options. When I start to scroll using mouse, page starts to scroll and expanded options are closed.

Scrollbars on the browser control

I cannot work out how to disable the scroll bars on the browser window. Is this possible?

Rework IBeforeResourceLoaded to enforce mime type requirement

Should enforce the setting of mimeType when a response is set.

something like this:

   interface IRequestResponse
   {
       property IRequest Request { IRequest get(); }
       void SetRedirect(String redirect);                      /// can throw
       void SetResponse(Stream stream, String mimeType);       /// can throw
   }

   interface class IBeforeResourceLoad
   {
        ReturnValue HandleBeforeResourceLoad(CefWebBrowser browserControl, IRequestResponse requestResponse);
   }