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

content/browser/tab_contents/render_view_host_manager.cc

 // Copyright (c) 2011 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/browser/tab_contents/render_view_host_manager.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
@@ skipping 44 matching lines @@
                                  SiteInstance* site_instance,
                                  int routing_id) {
   // Create a RenderViewHost, once we have an instance.  It is important to
   // immediately give this SiteInstance to a RenderViewHost so that it is
   // ref counted.
   if (!site_instance)
     site_instance = SiteInstance::CreateSiteInstance(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 {
   if (!render_view_host_)
     return NULL;
   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);
   if (!dest_render_view_host)
     return NULL;  // We weren't able to create a pending render view host.
 
   // If the current render_view_host_ isn't live, we should create it so
   // that we don't show a sad tab while the dest_render_view_host fetches
   // its first page.  (Bug 1145340)
   if (dest_render_view_host != render_view_host_ &&
@@ skipping 125 matching lines @@
   // looks for this TabContents based on a render view ID.  Instead, we just
   // leave the pending renderer around until the next navigation event
   // (Navigate, DidNavigate, etc), which will clean it up properly.
   // TODO(creis): All of this will go away when we move the cross-site logic
   // to ResourceDispatcherHost, so that we intercept responses rather than
   // navigation events.  (That's necessary to support onunload anyway.)  Once
   // we've made that change, we won't create a pending renderer until we know
   // 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) {
     // Ignore if we're not in a cross-site navigation.
     if (!cross_navigation_pending_)
       return;
 
     if (proceed) {
       // Ok to unload the current page, so proceed with the cross-site
       // navigation.  Note that if navigations are not currently suspended, it
@@ skipping 228 matching lines @@
   if (curr_entry) {
     DCHECK(!curr_entry->content_state().empty());
     // TODO(creis): Should send a message to the RenderView to let it know
     // we're about to switch away, so that it sends an UpdateState message.
   }
 
   pending_render_view_host_ = RenderViewHostFactory::Create(
       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.
     pending_render_view_host_->view()->Hide();
   } else {
     CancelPending();
   }
   return success;
 }
 
@@ skipping 43 matching lines @@
   // TODO(creis): Get the old RenderViewHost to send us an UpdateState message
   // before we destroy it.
   if (render_view_host_->view())
     render_view_host_->view()->Hide();
   RenderViewHost* old_render_view_host = render_view_host_;
 
   // Swap in the pending view and make it active.
   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.
   if (render_view_host_->view())
     render_view_host_->view()->Show();
   else
     delegate_->RenderViewGoneFromRenderManager(render_view_host_);
 
   // Make sure the size is up to date.  (Fix for bug 1079768.)
   delegate_->UpdateRenderViewSizeForRenderManager();
@@ skipping 117 matching lines @@
   // cross navigating.
   DCHECK(!cross_navigation_pending_);
   return render_view_host_;
 }
 
 void RenderViewHostManager::CancelPending() {
   RenderViewHost* pending_render_view_host = pending_render_view_host_;
   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();
 }
 
 void RenderViewHostManager::RenderViewDeleted(RenderViewHost* rvh) {
   // We are doing this in order to work around and to track a crasher
   // (http://crbug.com/23411) where it seems that pending_render_view_host_ is
   // deleted (not sure from where) but not NULLed.
   if (rvh == pending_render_view_host_) {
     // If you hit this NOTREACHED, please report it in the following bug
     // http://crbug.com/23411 Make sure to include what you were doing when it
@@ skipping 44 matching lines @@
       Source<NavigationController>(&delegate_->GetControllerForRenderManager()),
       Details<RenderViewHostSwitchedDetails>(&details));
 
   // This will cause the old RenderViewHost to delete itself.
   old_render_view_host->Shutdown();
 
   // Let the task manager know that we've swapped RenderViewHosts, since it
   // might need to update its process groupings.
   delegate_->NotifySwappedFromRenderManager();
 }