Allow specifying a custom CefClient to use with wxWebViewChromium

This opens many customization possibilities beyond those provided by
wxWebView API and also allows to process CEF IPC messages much more
efficiently than what is possible using wxEvents.

Closes #24336.

build/bakefiles/files.bkl

@@ -2708,6 +2708,7 @@ IMPORTANT: please read docs/tech/tn0016.txt before modifying this file!
     wx/webviewarchivehandler.h
     wx/webviewfshandler.h
     wx/webview_chromium.h
+    wx/webview_chromium_impl.h
 </set>
 <set var="WEBVIEW_HDR" hints="files">
     $(WEBVIEW_HDR_PLATFORM)

build/cmake/files.cmake

@@ -2533,6 +2533,7 @@ set(WEBVIEW_CMN_HDR
     wx/webviewarchivehandler.h
     wx/webviewfshandler.h
     wx/webview_chromium.h
+    wx/webview_chromium_impl.h
 )
 
 set(WEBVIEW_OSX_SHARED_HDR

build/files

@@ -2486,6 +2486,7 @@ WEBVIEW_CMN_HDR =
     wx/webviewarchivehandler.h
     wx/webviewfshandler.h
     wx/webview_chromium.h
+    wx/webview_chromium_impl.h
 
 WEBVIEW_OSX_SHARED_HDR =
     wx/osx/webviewhistoryitem_webkit.h

build/msw/wx_webview.vcxproj

@@ -507,6 +507,7 @@
     <ClInclude Include="..\..\include\wx\webviewfshandler.h" />
     <ClInclude Include="..\..\include\wx\webview_chromium.h" />
     <ClInclude Include="..\..\include\wx\msw\webview_edge.h" />
+    <ClInclude Include="..\..\include\wx\webview_chromium_impl.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">

build/msw/wx_webview.vcxproj.filters

@@ -61,6 +61,9 @@
     <ClInclude Include="..\..\include\wx\webview_chromium.h">
       <Filter>Common Headers</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\include\wx\webview_chromium_impl.h">
+      <Filter>Common Headers</Filter>
+    </ClInclude>
     <ClInclude Include="..\..\include\wx\webviewarchivehandler.h">
       <Filter>Common Headers</Filter>
     </ClInclude>