Fail gracefully if the active profile can't be found in the ProfileInfoCache

chrome/browser/chrome_browser_main.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/chrome_browser_main.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 356 matching lines @@
   // signed out, then we should show the user manager instead. By switching
   // the active profile to the guest profile we ensure that no
   // browser windows will be opened for the guest profile.
   if (switches::IsNewProfileManagement() &&
       profile &&
       !profile->IsGuestSession()) {
     ProfileInfoCache& cache =
         g_browser_process->profile_manager()->GetProfileInfoCache();
     size_t profile_index = cache.GetIndexOfProfileWithPath(profile_path);
 
-    if (cache.ProfileIsSigninRequiredAtIndex(profile_index))
+    if (profile_index != std::string::npos &&
+        cache.ProfileIsSigninRequiredAtIndex(profile_index)) {
       profile = g_browser_process->profile_manager()->GetProfile(
           ProfileManager::GetGuestProfilePath());
+    }
   }
 #endif  // defined(OS_CHROMEOS) || defined(OS_ANDROID)
   if (profile) {
     UMA_HISTOGRAM_LONG_TIMES(
         "Startup.CreateFirstProfile", base::Time::Now() - start);
     return profile;
   }
 
 #if !defined(OS_WIN)
   // TODO(port): fix this.  See comments near the definition of
@@ skipping 1338 matching lines @@
   chromeos::CrosSettings::Shutdown();
 #endif  // defined(OS_CHROMEOS)
 #endif  // defined(OS_ANDROID)
 }
 
 // Public members:
 
 void ChromeBrowserMainParts::AddParts(ChromeBrowserMainExtraParts* parts) {
   chrome_extra_parts_.push_back(parts);
 }