Fixes possible deadlock between history and bookmarks. The deadlock

chrome/browser/profiles/profile_impl.cc

Index: chrome/browser/profiles/profile_impl.cc
diff --git a/chrome/browser/profiles/profile_impl.cc b/chrome/browser/profiles/profile_impl.cc
index 83e45dfd8406cdac737e08937dd24ebeb45231b2..e698177a5c3e8b48a6b0f6e312e0b5a1077bd9ea 100644
--- a/chrome/browser/profiles/profile_impl.cc
+++ b/chrome/browser/profiles/profile_impl.cc
@@ -804,6 +804,15 @@ ProfileImpl::~ProfileImpl() {
     default_request_context_ = NULL;
   }
 
+  if (bookmark_bar_model_.get()) {
+    // It's possible that bookmarks haven't loaded and history is waiting for
+    // bookmarks to complete loading. In such a situation history can't
+    // shutdown. To break the deadlock we tell BookmarkModel it's about to be
+    // deleted so that it can release the signal history is waiting on, allowing
+    // history to shutdown. In such a scenario history sees an incorrect view of
+    // bookmarks, but it's better than a deadlock.
+    bookmark_bar_model_->Cleanup();
+  }
   // HistoryService may call into the BookmarkModel, as such we need to
   // delete HistoryService before the BookmarkModel. The destructor for
   // HistoryService will join with HistoryService's backend thread so that