Rewrite raw pointers reported by clang plugin (see #3239)

Found using a CEF build with clang_use_chrome_plugins=true
and treat_warnings_as_errors=false.

This change rewrites remaining raw pointers reported by
chromium-rawptr checker and fixes a build error reported
by StackAllocatedChecker.

libcef/renderer/blink_glue.cc

@@ -282,6 +282,7 @@ void RegisterURLSchemeAsSupportingFetchAPI(const blink::WebString& scheme) {
 }
 
 struct CefScriptForbiddenScope::Impl {
+  STACK_ALLOCATED_IGNORE()
   blink::ScriptForbiddenScope scope_;
 };