Avoid exiting the renderer process if it has a pending render view.

content/browser/tab_contents/render_view_host_manager.cc

Index: content/browser/tab_contents/render_view_host_manager.cc
diff --git a/content/browser/tab_contents/render_view_host_manager.cc b/content/browser/tab_contents/render_view_host_manager.cc
index d08f6abc332278958a504bf9c038105c8726d455..e7aa7eed538f3adab658542642ed0e6fa89ea172 100644
--- a/content/browser/tab_contents/render_view_host_manager.cc
+++ b/content/browser/tab_contents/render_view_host_manager.cc
@@ -62,6 +62,10 @@ void RenderViewHostManager::Init(Profile* profile,
   render_view_host_ = RenderViewHostFactory::Create(
       site_instance, render_view_delegate_, routing_id, delegate_->
       GetControllerForRenderManager().session_storage_namespace());
+
+  // Keep track of renderer processes as they start to shut down.
+  registrar_.Add(this, NotificationType::RENDERER_PROCESS_CLOSING,
+                 NotificationService::AllSources());
 }
 
 RenderWidgetHostView* RenderViewHostManager::GetRenderWidgetHostView() const {
@@ -70,6 +74,19 @@ RenderWidgetHostView* RenderViewHostManager::GetRenderWidgetHostView() const {
   return render_view_host_->view();
 }
 
+void RenderViewHostManager::Observe(NotificationType type,
+                                    const NotificationSource& source,
+                                    const NotificationDetails& details) {
+  switch (type.value) {
+    case NotificationType::RENDERER_PROCESS_CLOSING:
+      RendererProcessClosing(Source<RenderProcessHost>(source).ptr());
+      break;
+
+    default:
+      NOTREACHED();
+  }
+}
+
 RenderViewHost* RenderViewHostManager::Navigate(const NavigationEntry& entry) {
   // Create a pending RenderViewHost. It will give us the one we should use
   RenderViewHost* dest_render_view_host = UpdateRendererStateForNavigate(entry);
@@ -215,6 +232,12 @@ void RenderViewHostManager::RendererAbortedProvisionalLoad(
   // the response is not a download.
 }
 
+void RenderViewHostManager::RendererProcessClosing(
+    RenderProcessHost* render_process_host) {
+  // TODO(creis): Don't schedule new navigations in RenderViewHosts of this
+  // process.  (Part of http://crbug.com/65953.)
+}
+
 void RenderViewHostManager::ShouldClosePage(bool for_cross_site_transition,
                                             bool proceed) {
   if (for_cross_site_transition) {
@@ -463,6 +486,9 @@ bool RenderViewHostManager::CreatePendingRenderView(
       instance, render_view_delegate_, MSG_ROUTING_NONE, delegate_->
       GetControllerForRenderManager().session_storage_namespace());
 
+  // Prevent the process from exiting while we're trying to use it.
+  pending_render_view_host_->process()->AddPendingView();
+
   bool success = InitRenderView(pending_render_view_host_, entry);
   if (success) {
     // Don't show the view until we get a DidNavigate from it.
@@ -526,6 +552,9 @@ void RenderViewHostManager::CommitPending() {
   render_view_host_ = pending_render_view_host_;
   pending_render_view_host_ = NULL;
 
+  // The process will no longer try to exit, so we can decrement the count.
+  render_view_host_->process()->RemovePendingView();
+
   // If the view is gone, then this RenderViewHost died while it was hidden.
   // We ignored the RenderViewGone call at the time, so we should send it now
   // to make sure the sad tab shows up, etc.
@@ -663,6 +692,9 @@ void RenderViewHostManager::CancelPending() {
   pending_render_view_host_ = NULL;
   pending_render_view_host->Shutdown();
 
+  // We no longer need to prevent the process from exiting.
+  pending_render_view_host->process()->RemovePendingView();

[Matt Perry, 2011/05/10 01:14:02]

does it matter if this comes before or after Shutdown? (I'm wondering if
Shutdown might synchronously NULL-out process).

[Charlie Reis, 2011/05/10 01:33:09]

That's a good question-- Shutdown doesn't null out the process, but it does send
a shutdown-related message.  It should probably come before to avoid a race. 
I'll fix it in the next patch set.

+
   pending_web_ui_.reset();
 }