Adds some debugging code in hopes of tracking down a...

chrome/browser/browser_shutdown.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/browser_shutdown.h"
 
 #include "app/resource_bundle.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/histogram.h"
@@ skipping 47 matching lines @@
     // since we can't safely count the number of plugin processes from this
     // thread, and we'd really like to avoid anything which might add further
     // delays to shutdown time.
     shutdown_num_processes_ = static_cast<int>(RenderProcessHost::size());
     shutdown_started_ = Time::Now();
 
     // Call FastShutdown on all of the RenderProcessHosts.  This will be
     // a no-op in some cases, so we still need to go through the normal
     // shutdown path for the ones that didn't exit here.
     shutdown_num_processes_slow_ = 0;
+    size_t start_rph_size = RenderProcessHost::size();
     for (RenderProcessHost::iterator hosts = RenderProcessHost::begin();
          hosts != RenderProcessHost::end();
          ++hosts) {
       RenderProcessHost* rph = hosts->second;
       if (!rph->FastShutdownIfPossible())
         // TODO(ojan): I think now that we deal with beforeunload/unload
         // higher up, it's not possible to get here. Confirm this and change
         // FastShutdownIfPossible to just be FastShutdown.
         shutdown_num_processes_slow_++;
+      // The number of RPHs should not have changed as the result of invoking
+      // FastShutdownIfPossible.
+      CHECK(start_rph_size == RenderProcessHost::size());
     }
   }
 }
 
 FilePath GetShutdownMsPath() {
   FilePath shutdown_ms_file;
   PathService::Get(base::DIR_TEMP, &shutdown_ms_file);
   return shutdown_ms_file.AppendASCII(kShutdownMsFile);
 }
 
@@ skipping 113 matching lines @@
                           TimeDelta::FromMilliseconds(shutdown_ms));
       UMA_HISTOGRAM_TIMES(time_per.c_str(),
                           TimeDelta::FromMilliseconds(shutdown_ms / num_procs));
       UMA_HISTOGRAM_COUNTS_100("Shutdown.renderers.total", num_procs);
       UMA_HISTOGRAM_COUNTS_100("Shutdown.renderers.slow", num_procs_slow);
     }
   }
 }
 
 }  // namespace browser_shutdown