Don't swap out the old RenderFrameHost until the new one commits.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index 267d690be28b66b93e3fccc5d5bf6f4dfe35c539..2a1cb0398c26f4e62e33eae8578a63d2cb820f06 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -139,8 +139,6 @@ const int RenderViewHostImpl::kUnloadTimeoutMS = 1000;
 // static
 bool RenderViewHostImpl::IsRVHStateActive(RenderViewHostImplState rvh_state) {
   if (rvh_state == STATE_DEFAULT ||
-      rvh_state == STATE_WAITING_FOR_UNLOAD_ACK ||
-      rvh_state == STATE_WAITING_FOR_COMMIT ||
       rvh_state == STATE_WAITING_FOR_CLOSE)
     return true;
   return false;
@@ -540,9 +538,6 @@ void RenderViewHostImpl::OnSwappedOut(bool timed_out) {
   }
 
   switch (rvh_state_) {
-    case STATE_WAITING_FOR_UNLOAD_ACK:
-      SetState(STATE_WAITING_FOR_COMMIT);
-      break;
     case STATE_PENDING_SWAP_OUT:
       SetState(STATE_SWAPPED_OUT);
       break;
@@ -555,26 +550,6 @@ void RenderViewHostImpl::OnSwappedOut(bool timed_out) {
   }
 }
 
-void RenderViewHostImpl::WasSwappedOut(
-    const base::Closure& pending_delete_on_swap_out) {
-  Send(new ViewMsg_WasSwappedOut(GetRoutingID()));
-  if (rvh_state_ == STATE_WAITING_FOR_UNLOAD_ACK) {
-    SetState(STATE_PENDING_SWAP_OUT);
-    if (!instance_->active_view_count())
-      SetPendingShutdown(pending_delete_on_swap_out);
-  } else if (rvh_state_ == STATE_WAITING_FOR_COMMIT) {
-    SetState(STATE_SWAPPED_OUT);
-  } else if (rvh_state_ == STATE_DEFAULT) {
-    // When the RenderView is not live, the RenderFrameHostManager will call
-    // CommitPending directly, without calling SwapOut on the old RVH. This will
-    // cause WasSwappedOut to be called directly on the live old RVH.
-    DCHECK(!IsRenderViewLive());
-    SetState(STATE_SWAPPED_OUT);
-  } else {
-    NOTREACHED();
-  }
-}
-
 void RenderViewHostImpl::SetPendingShutdown(const base::Closure& on_swap_out) {
   pending_shutdown_on_swap_out_ = on_swap_out;
   SetState(STATE_PENDING_SHUTDOWN);
@@ -1367,8 +1342,7 @@ void RenderViewHostImpl::DidCancelPopupMenu() {
 #endif
 
 bool RenderViewHostImpl::IsWaitingForUnloadACK() const {
-  return rvh_state_ == STATE_WAITING_FOR_UNLOAD_ACK ||
-         rvh_state_ == STATE_WAITING_FOR_CLOSE ||
+  return rvh_state_ == STATE_WAITING_FOR_CLOSE ||
          rvh_state_ == STATE_PENDING_SHUTDOWN ||
          rvh_state_ == STATE_PENDING_SWAP_OUT;
 }