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 1f6101d375b5172ea843a7e52505c5285766a6aa..b64b5ae442680fd3f9461e384946de87301ed69a 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -923,6 +923,15 @@ void RenderFrameHostManager::DiscardUnusedFrame(
   }
 
   if (render_frame_host) {
+    if (!frame_tree_node_->IsMainFrame() &&
+        SiteIsolationPolicy::IsSwappedOutStateForbidden()) {
+      // Clean up the unused RenderFrame in the renderer process for any
+      // subframe. The main frame is going to be cleaned up by RenderViewHost
+      // deleting RenderView.
+      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();