Closing a guest session clears all browsing history.

chrome/browser/browsing_data/browsing_data_remover.cc

Index: chrome/browser/browsing_data/browsing_data_remover.cc
diff --git a/chrome/browser/browsing_data/browsing_data_remover.cc b/chrome/browser/browsing_data/browsing_data_remover.cc
index 4e3b3653e819a978ef320fb89b8fbd26efa739f6..797af9756099115b33a5a80679af510effa7b3ca 100644
--- a/chrome/browser/browsing_data/browsing_data_remover.cc
+++ b/chrome/browser/browsing_data/browsing_data_remover.cc
@@ -647,8 +647,11 @@ void BrowsingDataRemover::RemoveImpl(int remove_mask,
         content::StoragePartition::REMOVE_DATA_MASK_WEBRTC_IDENTITY;
 
 #if defined(ENABLE_EXTENSIONS)
-    // Clear the ephemeral apps cache.
-    EphemeralAppService::Get(profile_)->ClearCachedApps();
+    // Clear the ephemeral apps cache. This is NULL while testing.
+    EphemeralAppService* ephemeral_app_service =
+        EphemeralAppService::Get(profile_);
+    if (ephemeral_app_service)
+      ephemeral_app_service->ClearCachedApps();
 #endif
   }