Prepare MimeHanderViewContainer for removing swapped out RenderFrame.

extensions/renderer/guest_view/mime_handler_view/mime_handler_view_container.cc

Index: extensions/renderer/guest_view/mime_handler_view/mime_handler_view_container.cc
diff --git a/extensions/renderer/guest_view/mime_handler_view/mime_handler_view_container.cc b/extensions/renderer/guest_view/mime_handler_view/mime_handler_view_container.cc
index e3512823efa7592462c504a7f775375966b1bd41..3ac7e86a2e9b4de9f08788d38c0d330b6fcdafed 100644
--- a/extensions/renderer/guest_view/mime_handler_view/mime_handler_view_container.cc
+++ b/extensions/renderer/guest_view/mime_handler_view/mime_handler_view_container.cc
@@ -23,6 +23,7 @@
 #include "gin/wrappable.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
+#include "third_party/WebKit/public/web/WebRemoteFrame.h"
 #include "third_party/WebKit/public/web/WebView.h"
 
 namespace extensions {
@@ -235,8 +236,16 @@ void MimeHandlerViewContainer::PostMessage(v8::Isolate* isolate,
 
   v8::Context::Scope context_scope(
       render_frame()->GetWebFrame()->mainWorldScriptContext());
-  v8::Local<v8::Object> guest_proxy_window =
-      guest_proxy_frame->mainWorldScriptContext()->Global();
+
+  v8::Local<v8::Object> guest_proxy_window;
+  if (guest_proxy_frame->isWebLocalFrame()) {

[Fady Samuel, 2015/09/14 15:39:26]

A comment or helper method would be very useful here because it's not clear
what's going on.

[nasko, 2015/09/14 16:24:21]

Done.

+    guest_proxy_window =
+        guest_proxy_frame->mainWorldScriptContext()->Global();
+  } else {
+    guest_proxy_window = guest_proxy_frame->toWebRemoteFrame()
+                             ->deprecatedMainWorldScriptContext()
+                             ->Global();
+  }
   gin::Dictionary window_object(isolate, guest_proxy_window);
   v8::Local<v8::Function> post_message;
   if (!window_object.Get(std::string(kPostMessageName), &post_message))
@@ -247,7 +256,7 @@ void MimeHandlerViewContainer::PostMessage(v8::Isolate* isolate,
       // Post the message to any domain inside the browser plugin. The embedder
       // should already know what is embedded.
       gin::StringToV8(isolate, "*")};
-  guest_proxy_frame->callFunctionEvenIfScriptDisabled(
+  render_frame()->GetWebFrame()->callFunctionEvenIfScriptDisabled(

[Fady Samuel, 2015/09/14 15:38:05]

I thought we also wanted to avoid using callFunctionEvenIfScriptDisabled?

[nasko, 2015/09/14 15:39:19]

Yes, but on WebRemoteFrame, since it is not implemented. This calls it on the
WebLocalFrame, which means we plumb the postMessage call almost identically to
how it works in regular cases.

       post_message.As<v8::Function>(),
       guest_proxy_window,
       arraysize(args),