Fix a race condition in BrowsingDataRemover.

chrome/browser/browsing_data/browsing_data_remover.h

Index: chrome/browser/browsing_data/browsing_data_remover.h
diff --git a/chrome/browser/browsing_data/browsing_data_remover.h b/chrome/browser/browsing_data/browsing_data_remover.h
index c04bbe4852a44914893e28b0e8fcf8cbac380e27..6806a33537c6f799d4411d401b649705e69a2f63 100644
--- a/chrome/browser/browsing_data/browsing_data_remover.h
+++ b/chrome/browser/browsing_data/browsing_data_remover.h
@@ -453,6 +453,7 @@ class BrowsingDataRemover : public KeyedService
   uint32_t deauthorize_flash_content_licenses_request_id_ = 0;
   // True if we're waiting for various data to be deleted.
   // These may only be accessed from UI thread in order to avoid races!
+  bool waiting_for_synchronous_clear_operations_ = false;
   bool waiting_for_clear_autofill_origin_urls_ = false;
   bool waiting_for_clear_cache_ = false;
   bool waiting_for_clear_channel_ids_ = false;