Make wxWebViewChromium::OnSize() private

Also make a couple of cosmetic/style fixes.

No real changes, just don't leave the event handler public when it
doesn't have to be.

include/wx/webview_chromium.h

@@ -43,8 +43,6 @@ public:
 
     ~wxWebViewChromium();
 
-    void OnSize(wxSizeEvent &event);
-
     void SetPageSource(const wxString& pageSource);
 
     void SetPageText(const wxString& pageText);
@@ -136,6 +134,8 @@ private:
     // Common part of all ctors.
     void Init();
 
+    void OnSize(wxSizeEvent& event);
+
     // Actually create the browser: this can only be done once the window is
     // created in wxGTK.
     bool DoCreateBrowser(const wxString& url);