Do not filter IPC messages until the new RVH commits, to avoid a race.

content/browser/tab_contents/tab_contents.cc

Index: content/browser/tab_contents/tab_contents.cc
diff --git a/content/browser/tab_contents/tab_contents.cc b/content/browser/tab_contents/tab_contents.cc
index 013f8d56eca31777e282c120ae83f4b9465560df..962abc35e8ce43b76607ee26033ee5dfd356e61d 100644
--- a/content/browser/tab_contents/tab_contents.cc
+++ b/content/browser/tab_contents/tab_contents.cc
@@ -103,12 +103,6 @@
 // - The previous renderer is kept swapped out in RenderViewHostManager in case
 //   the user goes back.  The process only stays live if another tab is using
 //   it, but if so, the existing frame relationships will be maintained.
-//
-// It is possible that we trigger a new navigation after we have received
-// a SwapOut_ACK message but before the FrameNavigation has been confirmed.
-// In this case the old RVH has been swapped out but the new one has not
-// replaced it, yet. Therefore, we cancel the pending RVH and skip the unloading
-// of the old RVH.
 
 using content::DevToolsAgentHost;
 using content::DevToolsAgentHostRegistry;