CrOS: Add print statements to help debug BrowserProcessImpl::Unpin crash.

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 <stddef.h>
 
 #include <algorithm>
 #include <map>
@@ skipping 1307 matching lines @@
   if (IsShuttingDown()) {
     // TODO(crbug.com/113031, crbug.com/625646): Temporary instrumentation.
     base::debug::SetCrashKeyToStackTrace(crash_keys::kBrowserUnpinTrace,
                                          release_last_reference_callstack_);
     CHECK(false);
   }
 }
 
 void BrowserProcessImpl::Unpin() {
   DCHECK(CalledOnValidThread());
+  LOG(ERROR) << "Unpin";
+
   release_last_reference_callstack_ = base::debug::StackTrace();
 
   shutting_down_ = true;
 #if BUILDFLAG(ENABLE_PRINTING)
   // Wait for the pending print jobs to finish. Don't do this later, since
   // this might cause a nested message loop to run, and we don't want pending
   // tasks to run once teardown has started.
   print_job_manager_->Shutdown();
 #endif
 
@@ skipping 75 matching lines @@
 }
 
 void BrowserProcessImpl::OnAutoupdateTimer() {
   if (CanAutorestartForUpdate()) {
     DLOG(WARNING) << "Detected update.  Restarting browser.";
     RestartBackgroundInstance();
   }
 }
 
 #endif  // (defined(OS_WIN) || defined(OS_LINUX)) && !defined(OS_CHROMEOS)