Fix a crash on clearing power consumption auditing data in guest mode.

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 2dc65591be3577ff8365d0425ca959f608f7940a..d3682081fd312dd98e2dffab283fffe1df17f8e0 100644
--- a/chrome/browser/browsing_data/browsing_data_remover.cc
+++ b/chrome/browser/browsing_data/browsing_data_remover.cc
@@ -310,7 +310,8 @@ void BrowsingDataRemover::RemoveImpl(int remove_mask,
     // that were visited.
     power::OriginPowerMap* origin_power_map =
         power::OriginPowerMapFactory::GetForBrowserContext(profile_);
-    origin_power_map->ClearOriginMap();
+    if (origin_power_map)
+      origin_power_map->ClearOriginMap();
 
     // Need to clear the host cache and accumulated speculative data, as it also
     // reveals some history: we have no mechanism to track when these items were