Fix the process creation problem. This forces transitions between...

chrome/browser/tab_contents/render_view_host_manager.cc

 // Copyright (c) 2006-2008 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 "chrome/browser/tab_contents/render_view_host_manager.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "chrome/browser/dom_ui/dom_ui.h"
 #include "chrome/browser/dom_ui/dom_ui_factory.h"
@@ skipping 259 matching lines @@
   CHECK(render_view_host_ != deleted_rvh);
   CHECK(pending_render_view_host_ != deleted_rvh);
 }
 
 bool RenderViewHostManager::ShouldTransitionCrossSite() {
   // True if we are using process-per-site-instance (default) or
   // process-per-site (kProcessPerSite).
   return !CommandLine::ForCurrentProcess()->HasSwitch(switches::kProcessPerTab);
 }
 
-bool RenderViewHostManager::ShouldSwapRenderViewsForNavigation(
+bool RenderViewHostManager::ShouldSwapProcessesForNavigation(
     const NavigationEntry* cur_entry,
     const NavigationEntry* new_entry) const {
   if (!cur_entry || !new_entry)
     return false;
 
   // We can't switch a RenderView between view source and non-view source mode
   // without screwing up the session history sometimes (when navigating between
   // "view-source:http://foo.com/" and "http://foo.com/", WebKit doesn't treat
   // it as a new navigation). So require a view switch.
   if (cur_entry->IsViewSourceMode() != new_entry->IsViewSourceMode())
@@ skipping 80 matching lines @@
   // script-based navigations, but for now, it could place some pages in a
   // new process unnecessarily.  We should only hit this case if a page tries
   // to open a new tab to an interstitial-inducing URL, and then navigates
   // the page to a different same-site URL.  (This seems very unlikely in
   // practice.)
   const GURL& current_url = (curr_entry) ? curr_entry->url() :
       curr_instance->site();
 
   if (SiteInstance::IsSameWebSite(current_url, dest_url)) {
     return curr_instance;
+  } else if (ShouldSwapProcessesForNavigation(curr_entry, &entry)) {
+    // When we're swapping, we need to force the site instance AND browsing
+    // instance to be new ones. This prevents some cases where we'll re-use
+    // processes opened from the New Tab Page because all NTP's have the same
+    // BrowsingInstance.

[Charlie Reis, 2009/04/16 22:00:56]

I had trouble following the last sentence.  Perhaps this?

This addresses special cases where we use a single BrowsingInstance for all
pages of a certain type (e.g., New Tab Pages), keeping them in the same process.

+    return SiteInstance::CreateSiteInstance(
+        delegate_->GetControllerForRenderManager()->profile());
   } else {
     // Start the new renderer in a new SiteInstance, but in the current
     // BrowsingInstance.  It is important to immediately give this new
     // SiteInstance to a RenderViewHost (if it is different than our current
     // SiteInstance), so that it is ref counted.  This will happen in
     // CreatePendingRenderView.
     return curr_instance->GetRelatedSiteInstance(dest_url);
   }
 }
 
@@ skipping 91 matching lines @@
   SiteInstance* curr_instance = render_view_host_->site_instance();
 
   // Determine if we need a new SiteInstance for this entry.
   // Again, new_instance won't be deleted before the end of this method, so it
   // is safe to use a normal pointer here.
   SiteInstance* new_instance = curr_instance;
   if (ShouldTransitionCrossSite())
     new_instance = GetSiteInstanceForEntry(entry, curr_instance);
 
   if (new_instance != curr_instance ||
-      ShouldSwapRenderViewsForNavigation(
+      ShouldSwapProcessesForNavigation(
           delegate_->GetLastCommittedNavigationEntryForRenderManager(),
           &entry)) {
     // New SiteInstance.
     DCHECK(!cross_navigation_pending_);
 
     // Create a pending RVH and navigate it.
     bool success = CreatePendingRenderView(new_instance);
     if (!success)
       return NULL;
 
@@ skipping 54 matching lines @@
 
   pending_dom_ui_.reset();
 }
 
 void RenderViewHostManager::CrossSiteNavigationCanceled() {
   DCHECK(cross_navigation_pending_);
   cross_navigation_pending_ = false;
   if (pending_render_view_host_)
     CancelPending();
 }