Ensure incognito TestingProfiles are incognito for their whole lifetime.

chrome/test/base/testing_profile_manager.cc

Index: chrome/test/base/testing_profile_manager.cc
diff --git a/chrome/test/base/testing_profile_manager.cc b/chrome/test/base/testing_profile_manager.cc
index 0bbc4ee6c65fe56ac85b9d8c3b883880d1598a59..2d49f6db3679fc2b34919cb26915f6bfe630d98c 100644
--- a/chrome/test/base/testing_profile_manager.cc
+++ b/chrome/test/base/testing_profile_manager.cc
@@ -118,11 +118,6 @@ TestingProfile* TestingProfileManager::CreateTestingProfile(
 TestingProfile* TestingProfileManager::CreateGuestProfile() {
   DCHECK(called_set_up_);
 
-  // Set up a profile with an off the record profile.
-  TestingProfile::Builder otr_builder;
-  otr_builder.SetIncognito();
-  scoped_ptr<TestingProfile> otr_profile(otr_builder.Build());
-
   // Create the profile and register it.
   TestingProfile::Builder builder;
   builder.SetGuestSession();
@@ -132,8 +127,9 @@ TestingProfile* TestingProfileManager::CreateGuestProfile() {
   TestingProfile* profile = builder.Build().release();
   profile->set_profile_name(kGuestProfileName);
 
-  otr_profile->SetOriginalProfile(profile);
-  profile->SetOffTheRecordProfile(otr_profile.PassAs<Profile>());
+  // Set up a profile with an off the record profile.
+  TestingProfile::Builder().BuildIncognito(profile);
+
   profile_manager_->AddProfile(profile);  // Takes ownership.
   profile_manager_->SetGuestProfilePrefs(profile);