Core - Remove remaining Plugin API (followup)

- Remove CefWebPluginInfoVisitorAdapter. from Net Core vcxproj
- Update BrowserProcessHandler example to set a different preference (the plugin ones will eventually be removed from Chromium)

Follow up to 0ac43cf

Issue #4045

Author: amaitland

CefSharp.Core.Runtime/CefSharp.Core.Runtime.netcore.vcxproj

@@ -419,7 +419,6 @@
     <ClInclude Include="Internals\JavascriptCallbackFactory.h" />
     <ClInclude Include="Internals\MCefRefPtr.h" />
     <ClInclude Include="Internals\Messaging\Messages.h" />
-    <ClInclude Include="Internals\CefWebPluginInfoVisitorAdapter.h" />
     <ClInclude Include="Internals\RenderClientAdapter.h" />
     <ClInclude Include="Internals\ReportUnhandledExceptions.h" />
     <ClInclude Include="Internals\CefRequestCallbackWrapper.h" />

CefSharp.Core.Runtime/CefSharp.Core.Runtime.netcore.vcxproj.filters

@@ -310,9 +310,6 @@
     <ClInclude Include="Internals\CefSchemeHandlerFactoryAdapter.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="Internals\CefWebPluginInfoVisitorAdapter.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="Internals\CefResourceHandlerAdapter.h">
       <Filter>Header Files</Filter>
     </ClInclude>

CefSharp.Example/Handlers/BrowserProcessHandler.cs

@@ -72,9 +72,16 @@ protected override void OnContextInitialized()
             using (var context = Cef.GetGlobalRequestContext())
             {
                 string errorMessage;
+
                 //You can set most preferences using a `.` notation rather than having to create a complex set of dictionaries.
-                //The default is true, you can change to false to disable
-                context.SetPreference("webkit.webprefs.plugins_enabled", true, out errorMessage);
+                //The default is true, you can change to false to disable resizing of text areas
+                //This is just one example, there are many many configuration options avaliable via preferences
+                var success = context.SetPreference("webkit.webprefs.text_areas_are_resizable", true, out errorMessage);
+
+                if(!success)
+                {
+                    //Check the errorMessage for more details
+                }
 
                 //string error;
                 //var dicts = new List<string> { "en-GB", "en-US" };