Fix leaking of RenderFrames.

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index 11333116a64699f84dda0e004d8733a57365dbca..cf7813614787558c962d04c409c3732ad9d158e3 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -917,6 +917,12 @@ void RenderFrameHostManager::DiscardUnusedFrame(
   }
 
   if (render_frame_host) {
+    if (SiteIsolationPolicy::IsSwappedOutStateForbidden()) {
+      // Clean up the unused RenderFrame in the renderer process.
+      render_frame_host->Send(
+          new FrameMsg_Detach(render_frame_host->GetRoutingID()));
+    }
+
     // We won't be coming back, so delete this one.
     ShutdownProxiesIfLastActiveFrameInSiteInstance(render_frame_host.get());
     render_frame_host.reset();