ChromiumBrowserMBS.AddCrossOriginWhitelist(SourceOrigin as String, TargetProtocol as String, TargetDomain as String, AllowTargetSubdomains as Boolean) as Boolean

Var r as Boolean = ChromiumBrowserMBS.AddCrossOriginWhitelist("http://side1.mydomain.com", "http",  "side2.mydomain.com", false)

The same-origin policy restricts how scripts hosted from different origins (scheme + domain + port) can communicate. By default, scripts can only access resources with the same origin. Scripts hosted on the HTTP and HTTPS schemes (but no other schemes) can use the "Access-Control-Allow-Origin" header to allow cross-origin requests. For example, https://source.example.com can make XMLHttpRequest requests on http://target.example.com if the http://target.example.com request returns an "Access-Control-Allow-Origin: https://source.example.com" response header.

Scripts in separate frames or iframes and hosted from the same protocol and domain suffix can execute cross-origin JavaScript if both pages set the document.domain value to the same domain suffix. For example, scheme://foo.example.com and scheme://bar.example.com can communicate using JavaScript if both domains set document.domain="example.com".

This function is used to allow access to origins that would otherwise violate the same-origin policy. Scripts hosted underneath the fully qualified SourceOrigin URL (like http://www.example.com) will be allowed access to all resources hosted on the specified TargetProtocol and TargetDomain.
If TargetDomain is non-empty and AllowTargetSubdomains if false only exact domain matches will be allowed. If TargetDomain contains a top-level domain component (like "example.com") and AllowTargetSubdomains is true (1) sub-domain matches will be allowed. If TargetDomain is empty and AllowTargetSubdomains if true (1) all domains and IP addresses will be allowed.

This function cannot be used to bypass the restrictions on local or display isolated schemes. See the comments on CefRegisterCustomScheme for more information.

This function may be called on any thread. Returns true on success or false if SourceOrigin is invalid or the whitelist cannot be accessed.

ChromiumBrowserMBS.ClearCrossOriginWhitelist as Boolean

Var r as Boolean = ChromiumBrowserMBS.ClearCrossOriginWhitelist

Returns true on success or false if the whitelist cannot be accessed.

ChromiumBrowserMBS.LibVersion as Integer

Var b as ChromiumBrowserMBS = HTMLViewer1.ChromiumBrowserMBS
MsgBox str(b.LibVersion)

up to Xojo 2014r1 this is 607.
Xojo 2014r2 uses 1562.

ChromiumBrowserMBS.RegisterExtension(ExtensionName as String, javascriptCode as String) as Boolean

Returns true on success.

ChromiumBrowserMBS.RemoveCrossOriginWhitelist(SourceOrigin as String, TargetProtocol as String, TargetDomain as String, AllowTargetSubdomains as Boolean) as Boolean

Var r as Boolean = ChromiumBrowserMBS.AddCrossOriginWhitelist("http://side1.mydomain.com", "http",  "side2.mydomain.com", false)

Returns true on success or false if SourceOrigin is invalid or the whitelist cannot be accessed.