Move MainWorldScriptContext accessor/method from WebFrame to WebLocalFrame.

components/guest_view/renderer/guest_view_request.cc

Index: components/guest_view/renderer/guest_view_request.cc
diff --git a/components/guest_view/renderer/guest_view_request.cc b/components/guest_view/renderer/guest_view_request.cc
index ea96bc9b3c73c4094ece473c478d151abd856000..b9933af56350401066da842d6bdf4af7155b21b6 100644
--- a/components/guest_view/renderer/guest_view_request.cc
+++ b/components/guest_view/renderer/guest_view_request.cc
@@ -95,7 +95,7 @@ void GuestViewAttachRequest::HandleResponse(const IPC::Message& message) {
   // on top of out-of-process iframes. Remove it once the code is converted.
   v8::Local<v8::Value> window;
   if (frame->IsWebLocalFrame()) {
-    window = frame->MainWorldScriptContext()->Global();
+    window = frame->ToWebLocalFrame()->MainWorldScriptContext()->Global();
   } else {
     window = frame->ToWebRemoteFrame()->GlobalProxy();
   }