Add some instrumentation to BrowserProcessImpl.

chrome/browser/browser_process_impl.cc

 // Copyright (c) 2012 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_process_impl.h"
 
 #include <map>
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
+#include "base/debug/alias.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "chrome/browser/automation/automation_provider_list.h"
 #include "chrome/browser/background/background_mode_manager.h"
 #include "chrome/browser/browser_trial.h"
 #include "chrome/browser/chrome_browser_main.h"
 #include "chrome/browser/chrome_plugin_service_filter.h"
@@ skipping 213 matching lines @@
   message_loop->PostTask(FROM_HERE, MessageLoop::QuitClosure());
 }
 #elif defined(USE_X11)
 static void Signal(base::WaitableEvent* event) {
   event->Signal();
 }
 #endif
 
 unsigned int BrowserProcessImpl::AddRefModule() {
   DCHECK(CalledOnValidThread());
-  CHECK(!IsShuttingDown());
+
+  // CHECK(!IsShuttingDown());
+  if (IsShuttingDown()) {
+    // Copy the stacktrace which released the final reference onto our stack so
+    // it will be available in the crash report for inspection.
+    base::debug::StackTrace callstack = release_last_reference_callstack_;
+    base::debug::Alias(&callstack);
+    CHECK(false);
+  }
+
   did_start_ = true;
   module_ref_count_++;
   return module_ref_count_;
 }
 
 unsigned int BrowserProcessImpl::ReleaseModule() {
   DCHECK(CalledOnValidThread());
   DCHECK_NE(0u, module_ref_count_);
   module_ref_count_--;
   if (0 == module_ref_count_) {
+    release_last_reference_callstack_ = base::debug::StackTrace();
+
     CHECK(MessageLoop::current()->is_running());
     // Allow UI and IO threads to do blocking IO on shutdown, since we do a lot
     // of it on shutdown for valid reasons.
     base::ThreadRestrictions::SetIOAllowed(true);
     CHECK(!BrowserList::GetLastActive());
     BrowserThread::PostTask(
         BrowserThread::IO,
         FROM_HERE,
         base::Bind(base::IgnoreResult(&base::ThreadRestrictions::SetIOAllowed),
                    true));
@@ skipping 622 matching lines @@
 }
 
 void BrowserProcessImpl::OnAutoupdateTimer() {
   if (CanAutorestartForUpdate()) {
     DLOG(WARNING) << "Detected update.  Restarting browser.";
     RestartBackgroundInstance();
   }
 }
 
 #endif  // (defined(OS_WIN) || defined(OS_LINUX)) && !defined(OS_CHROMEOS)