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

chrome/browser/tab_contents/render_view_host_manager.h

 // 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.
 
 #ifndef CHROME_BROWSER_TAB_CONTENTS_RENDER_VIEW_HOST_MANAGER_H_
 #define CHROME_BROWSER_TAB_CONTENTS_RENDER_VIEW_HOST_MANAGER_H_
 
 #include "base/basictypes.h"
 #include "base/scoped_ptr.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
@@ skipping 168 matching lines @@
 
  private:
   friend class TestWebContents;
 
   // Returns whether this tab should transition to a new renderer for
   // cross-site URLs.  Enabled unless we see the --process-per-tab command line
   // switch.  Can be overridden in unit tests.
   bool ShouldTransitionCrossSite();
 
   // Returns true if the two navigation entries are incompatible in some way
-  // other than site instances. This will cause us to swap RenderViewHosts even
-  // if the site instances are the same. Either of the entries may be NULL.
-  bool ShouldSwapRenderViewsForNavigation(
+  // other than site instances. This will cause us to swap RenderViewHosts
+  // (and hence RenderProcessHosts) even if the site instance would otherwise
+  // be the same. It also forces new SiteInstances for these transitions.

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

"new SiteInstances and BrowsingInstances for these transitions."

Maybe also point out examples of when this is this case?  DOM UI pages, and soon
extensions (according to Matt).

+  // Either of the entries may be NULL.
+  bool ShouldSwapProcessesForNavigation(
       const NavigationEntry* cur_entry,
       const NavigationEntry* new_entry) const;
 
   // Returns an appropriate SiteInstance object for the given NavigationEntry,
   // possibly reusing the current SiteInstance.
   // Never called if --process-per-tab is used.
   SiteInstance* GetSiteInstanceForEntry(const NavigationEntry& entry,
                                         SiteInstance* curr_instance);
 
   // Helper method to create a pending RenderViewHost for a cross-site
@@ skipping 50 matching lines @@
 };
 
 // The "details" for a NOTIFY_RENDER_VIEW_HOST_CHANGED notification. The old
 // host can be NULL when the first RenderViewHost is set.
 struct RenderViewHostSwitchedDetails {
   RenderViewHost* old_host;
   RenderViewHost* new_host;
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_RENDER_VIEW_HOST_MANAGER_H_