Revert of Serve mojo WebUI resources from the same origin as the WebUI itself.

content/renderer/web_ui_mojo_context_state.h

Index: content/renderer/web_ui_mojo_context_state.h
diff --git a/content/renderer/web_ui_mojo_context_state.h b/content/renderer/web_ui_mojo_context_state.h
index 086011567215971bca291823b0803f95eb733c42..4aa12e5153231c4f9ead9170972564b201be5fa0 100644
--- a/content/renderer/web_ui_mojo_context_state.h
+++ b/content/renderer/web_ui_mojo_context_state.h
@@ -77,9 +77,6 @@
   // Set of modules we've fetched script from.
   std::set<std::string> fetched_modules_;
 
-  // The prefix to use for all module requests.
-  const std::string module_prefix_;
-
   DISALLOW_COPY_AND_ASSIGN(WebUIMojoContextState);
 };