Fix threading issues in aw form database

android_webview/browser/aw_form_database_service.h

Index: android_webview/browser/aw_form_database_service.h
diff --git a/android_webview/browser/aw_form_database_service.h b/android_webview/browser/aw_form_database_service.h
index c1cbc3720d2a9ac94705472aa64748893b34c1f0..2e988a262a6c87210c72c6a38a15760ecd2c34c7 100644
--- a/android_webview/browser/aw_form_database_service.h
+++ b/android_webview/browser/aw_form_database_service.h
@@ -7,6 +7,7 @@
 
 #include "base/basictypes.h"
 #include "base/files/file_path.h"
+#include "base/synchronization/lock.h"
 #include "base/synchronization/waitable_event.h"
 #include "components/autofill/core/browser/webdata/autofill_webdata_service.h"
 #include "components/webdata/common/web_data_service_consumer.h"
@@ -45,12 +46,14 @@ class AwFormDatabaseService : public WebDataServiceConsumer {
   // Cancels the currently pending WebDataService query, if there is one.
   void CancelPendingQuery();
 
-  void HasFormDataImpl();
+  void ClearFormDataLocked();
+  void HasFormDataLocked();
 
   // Stores the query handle when an async database query is executed.
   WebDataServiceBase::Handle pending_query_handle_;
   bool has_form_data_;
   base::WaitableEvent completion_;
+  base::Lock lock_;
 
   scoped_refptr<autofill::AutofillWebDataService> autofill_data_;
   scoped_refptr<WebDatabaseService> web_database_;