IGeolocationHandler.OnRequestGeolocationPermission - improve comment

GeolocationHandler Example - upgrade to properly use the callback.

Author: amaitland

CefSharp.WinForms.Example/Handlers/GeolocationHandler.cs

@@ -17,15 +17,22 @@ bool IGeolocationHandler.OnRequestGeolocationPermission(IWebBrowser browserContr
                 return false;
             }
 
-            using (callback)
+            var control = (Control)browserControl;
+
+            control.InvokeOnUiThreadIfRequired(delegate()
             {
-                var result = MessageBox.Show(String.Format("{0} wants to use your computer's location.  Allow?  ** You must set your Google API key in CefExample.Init() for this to work. **", requestingUrl), "Geolocation", MessageBoxButtons.YesNo);
+                //Callback wraps a managed resource, so we'll wrap in a using statement so it's always disposed of.
+                using (callback)
+                {
+                    var result = MessageBox.Show(string.Format("{0} wants to use your computer's location.  Allow?  ** You must set your Google API key in CefExample.Init() for this to work. **", requestingUrl), "Geolocation", MessageBoxButtons.YesNo);
 
-                callback.Continue(result == DialogResult.Yes);
-                callback.Dispose();
+                    callback.Continue(result == DialogResult.Yes);
+                }
+            });    
 
-                return result == DialogResult.Yes;
-            }
+            //To cancel the request immediately we'd return false here, as we're returning true
+            // the callback will be used to allow/deny the permission request.
+            return true;
         }
 
         void IGeolocationHandler.OnCancelGeolocationPermission(IWebBrowser browserControl, IBrowser browser, int requestId)

CefSharp/IGeolocationHandler.cs

@@ -18,7 +18,7 @@ public interface IGeolocationHandler
         /// <param name="requestingUrl">the URL requesting permission</param>
         /// <param name="requestId">the unique ID for the permission request</param>
         /// <param name="callback">Callback interface used for asynchronous continuation of geolocation permission requests.</param>
-        /// <returns>true to allow the request and false to deny</returns>
+        /// <returns>Return true and call IGeolocationCallback.Continue() either in this method or at a later time to continue or cancel the request. Return false to cancel the request immediately.</returns>
         bool OnRequestGeolocationPermission(IWebBrowser browserControl, IBrowser browser, string requestingUrl, int requestId, IGeolocationCallback callback);
 
         /// <summary>