Fire visibilityChange event on out-of-process iframes.

extensions/renderer/scoped_web_frame.cc

Index: extensions/renderer/scoped_web_frame.cc
diff --git a/extensions/renderer/scoped_web_frame.cc b/extensions/renderer/scoped_web_frame.cc
index 88c4098b5c33348f0773db33e396fdf0a980e353..4b4f4556f2eb362f728364b6d38e40d1888b27dc 100644
--- a/extensions/renderer/scoped_web_frame.cc
+++ b/extensions/renderer/scoped_web_frame.cc
@@ -9,7 +9,7 @@
 namespace extensions {
 
 ScopedWebFrame::ScopedWebFrame() : view_(nullptr), frame_(nullptr) {
-  view_ = blink::WebView::create(nullptr);
+  view_ = blink::WebView::create(nullptr, true);
   frame_ = blink::WebLocalFrame::create(
       blink::WebTreeScopeType::Document, nullptr);
   view_->setMainFrame(frame_);