Fix threading issues in aw form database

android_webview/browser/aw_form_database_service.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ANDROID_WEBVIEW_BROWSER_AW_FORM_DATABASE_SERVICE_H_
 #define ANDROID_WEBVIEW_BROWSER_AW_FORM_DATABASE_SERVICE_H_
 
 #include "base/basictypes.h"
 #include "base/files/file_path.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"
 #include "components/webdata/common/web_database_service.h"
 
+namespace base {
+class WaitableEvent;
+};
+
 namespace android_webview {
 
 // Handles the database operations necessary to implement the autocomplete
 // functionality. This includes creating and initializing the components that
 // handle the database backend, and providing a synchronous interface when
 // needed (the chromium database components have an async. interface).
 class AwFormDatabaseService : public WebDataServiceConsumer {
  public:
   AwFormDatabaseService(const base::FilePath path);
 
@@ skipping 10 matching lines @@
 
   scoped_refptr<autofill::AutofillWebDataService>
       get_autofill_webdata_service();
 
   // WebDataServiceConsumer implementation.
   virtual void OnWebDataServiceRequestDone(
       WebDataServiceBase::Handle h,
       const WDTypedResult* result) OVERRIDE;
 
  private:
-  // Cancels the currently pending WebDataService query, if there is one.
-  void CancelPendingQuery();
+  struct PendingQuery {
+    bool* result;
+    base::WaitableEvent* completion;
+  };
+  typedef std::map<WebDataServiceBase::Handle, PendingQuery> QueryMap;
 
-  void HasFormDataImpl();
+  void ClearFormDataImpl();
+  void HasFormDataImpl(base::WaitableEvent* completion, bool* result);
 
-  // Stores the query handle when an async database query is executed.
-  WebDataServiceBase::Handle pending_query_handle_;
-  bool has_form_data_;
-  base::WaitableEvent completion_;
+  QueryMap result_map_;
 
   scoped_refptr<autofill::AutofillWebDataService> autofill_data_;
   scoped_refptr<WebDatabaseService> web_database_;
 
   DISALLOW_COPY_AND_ASSIGN(AwFormDatabaseService);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_AW_FORM_DATABASE_SERVICE_H_