Clear UIThreadExtensionFunction::render_frame_host_ when RFH is gone.

extensions/browser/extension_function.h

Index: extensions/browser/extension_function.h
diff --git a/extensions/browser/extension_function.h b/extensions/browser/extension_function.h
index 3428ee7ddc0fdfbb96639e3535d75e27abc61bf3..7f1e998eb4d7c05c402ca6ddb2ba9630e0e9d8c2 100644
--- a/extensions/browser/extension_function.h
+++ b/extensions/browser/extension_function.h
@@ -498,6 +498,10 @@ class UIThreadExtensionFunction : public ExtensionFunction {
     return dispatcher_.get();
   }
 
+  void set_is_from_service_worker(bool value) {
+    is_from_service_worker_ = value;
+  }
+
   // Gets the "current" web contents if any. If there is no associated web
   // contents then defaults to the foremost one.
   // NOTE: "current" can mean different things in different contexts. You
@@ -539,6 +543,10 @@ class UIThreadExtensionFunction : public ExtensionFunction {
   // The RenderFrameHost we will send responses to.
   content::RenderFrameHost* render_frame_host_;
 
+  // Whether or not this ExtensionFunction was called by an extension Service
+  // Worker.
+  bool is_from_service_worker_;
+
   std::unique_ptr<RenderFrameHostTracker> tracker_;
 
   DelegateForTests* delegate_;