cros: Fix unit_tests crashes in GetBrand() on official builders

chrome/browser/google/google_brand_chromeos.cc

 // Copyright 2014 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 "base/basictypes.h"
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/prefs/pref_service.h"
@@ skipping 41 matching lines @@
          content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   g_brand_empty = true;
 }
 
 std::string GetBrand() {
   DCHECK(!content::BrowserThread::IsThreadInitialized(
              content::BrowserThread::UI) ||
          content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   if (g_brand_empty)
     return std::string();
-  DCHECK(g_browser_process->local_state());
+  // Unit tests do not have prefs.
+  if (!g_browser_process->local_state())
+    return std::string();
   return g_browser_process->local_state()->GetString(prefs::kRLZBrand);
 }
 
 void InitBrand(const base::Closure& callback) {
   ::chromeos::system::StatisticsProvider* provider =
       ::chromeos::system::StatisticsProvider::GetInstance();
   std::string brand;
   const bool found = provider->GetMachineStatistic(
       ::chromeos::system::kRlzBrandCodeKey, &brand);
   if (found && !brand.empty()) {
     SetBrand(callback, brand);
     return;
   }
 
   base::PostTaskAndReplyWithResult(
       base::WorkerPool::GetTaskRunner(false /* task_is_slow */).get(),
       FROM_HERE,
       base::Bind(&ReadBrandFromFile),
       base::Bind(&SetBrand, callback));
 }
 
 }  // namespace chromeos
 }  // namespace google_brand