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..ce2ecf98f6728cd25611395dca20364bdcb2d322 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -923,6 +923,16 @@ void RenderFrameHostManager::DiscardUnusedFrame(
   }
 
   if (render_frame_host) {
+    // 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, unless there are other active frames.
+    if (SiteIsolationPolicy::IsSwappedOutStateForbidden() &&
+        (render_frame_host->GetSiteInstance()->active_frame_count() > 1U ||

[Charlie Reis, 2015/11/04 21:28:30]

Did you have a concern about this?  I'm looking at it and it seems ok to me. 
Can you remind me which method of RFHM does the cleanup if active_frame_count()
is only 1?  As long as the conditions match, I think we should be good.

[nasko, 2015/12/10 21:26:52]

It is coincidentally right after this -
ShutdownProxiesIfLastActiveFrameInSiteInstance.

+         !frame_tree_node_->IsMainFrame())) {
+      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();