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

content/renderer/render_widget.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_widget.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 494 matching lines @@
   Send(new ViewHostMsg_RenderViewReady(routing_id_));
 }
 
 void RenderWidget::SetSwappedOut(bool is_swapped_out) {
   // We should only toggle between states.
   DCHECK(is_swapped_out_ != is_swapped_out);
   is_swapped_out_ = is_swapped_out;
 
   // If we are swapping out, we will call ReleaseProcess, allowing the process
   // to exit if all of its RenderViews are swapped out.  We wait until the
-  // WasSwappedOut call to do this, to avoid showing the sad tab.
+  // WasSwappedOut call to do this, to allow the unload handler to finish.
   // If we are swapping in, we call AddRefProcess to prevent the process from
   // exiting.
-  if (!is_swapped_out)
+  if (!is_swapped_out_)
     RenderProcess::current()->AddRefProcess();
 }
 
+void RenderWidget::WasSwappedOut() {
+  // If we have been swapped out and no one else is using this process,
+  // it's safe to exit now.
+  CHECK(is_swapped_out_);
+  RenderProcess::current()->ReleaseProcess();
+}
+
 void RenderWidget::EnableScreenMetricsEmulation(
     const WebDeviceEmulationParams& params) {
   if (!screen_metrics_emulator_)
     screen_metrics_emulator_.reset(new ScreenMetricsEmulator(this, params));
   else
     screen_metrics_emulator_->ChangeEmulationParams(params);
 }
 
 void RenderWidget::DisableScreenMetricsEmulation() {
   screen_metrics_emulator_.reset();
@@ skipping 59 matching lines @@
     IPC_MESSAGE_HANDLER(InputMsg_MouseCaptureLost, OnMouseCaptureLost)
     IPC_MESSAGE_HANDLER(InputMsg_SetFocus, OnSetFocus)
     IPC_MESSAGE_HANDLER(InputMsg_SyntheticGestureCompleted,
                         OnSyntheticGestureCompleted)
     IPC_MESSAGE_HANDLER(ViewMsg_Close, OnClose)
     IPC_MESSAGE_HANDLER(ViewMsg_CreatingNew_ACK, OnCreatingNewAck)
     IPC_MESSAGE_HANDLER(ViewMsg_Resize, OnResize)
     IPC_MESSAGE_HANDLER(ViewMsg_ChangeResizeRect, OnChangeResizeRect)
     IPC_MESSAGE_HANDLER(ViewMsg_WasHidden, OnWasHidden)
     IPC_MESSAGE_HANDLER(ViewMsg_WasShown, OnWasShown)
-    IPC_MESSAGE_HANDLER(ViewMsg_WasSwappedOut, OnWasSwappedOut)
     IPC_MESSAGE_HANDLER(ViewMsg_SetInputMethodActive, OnSetInputMethodActive)
     IPC_MESSAGE_HANDLER(ViewMsg_CandidateWindowShown, OnCandidateWindowShown)
     IPC_MESSAGE_HANDLER(ViewMsg_CandidateWindowUpdated,
                         OnCandidateWindowUpdated)
     IPC_MESSAGE_HANDLER(ViewMsg_CandidateWindowHidden, OnCandidateWindowHidden)
     IPC_MESSAGE_HANDLER(ViewMsg_Repaint, OnRepaint)
     IPC_MESSAGE_HANDLER(ViewMsg_SetTextDirection, OnSetTextDirection)
     IPC_MESSAGE_HANDLER(ViewMsg_Move_ACK, OnRequestMoveAck)
     IPC_MESSAGE_HANDLER(ViewMsg_UpdateScreenRects, OnUpdateScreenRects)
 #if defined(OS_ANDROID)
@@ skipping 185 matching lines @@
   // Generate a full repaint.
   if (compositor_) {
     ui::LatencyInfo swap_latency_info(latency_info);
     scoped_ptr<cc::SwapPromiseMonitor> latency_info_swap_promise_monitor(
         compositor_->CreateLatencyInfoSwapPromiseMonitor(&swap_latency_info));
     compositor_->SetNeedsForcedRedraw();
   }
   scheduleComposite();
 }
 
-void RenderWidget::OnWasSwappedOut() {
-  // If we have been swapped out and no one else is using this process,
-  // it's safe to exit now.  If we get swapped back in, we will call
-  // AddRefProcess in SetSwappedOut.
-  if (is_swapped_out_)
-    RenderProcess::current()->ReleaseProcess();
-}
-
 void RenderWidget::OnRequestMoveAck() {
   DCHECK(pending_window_rect_count_);
   pending_window_rect_count_--;
 }
 
 GURL RenderWidget::GetURLForGraphicsContext3D() {
   return GURL();
 }
 
 scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
@@ skipping 1331 matching lines @@
 void RenderWidget::RegisterVideoHoleFrame(RenderFrameImpl* frame) {
   video_hole_frames_.AddObserver(frame);
 }
 
 void RenderWidget::UnregisterVideoHoleFrame(RenderFrameImpl* frame) {
   video_hole_frames_.RemoveObserver(frame);
 }
 #endif  // defined(VIDEO_HOLE)
 
 }  // namespace content