Remove worker support of Web SQL Database.

public/platform/WebDatabaseObserver.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 19 matching lines @@
 
 #ifndef WebDatabaseObserver_h
 #define WebDatabaseObserver_h
 
 namespace blink {
 
 class WebString;
 
 class WebDatabaseObserver {
 public:
+    // FIXME: |isSyncDatabse| arguments are alwyas |false|. We should remove them.
+
     virtual void databaseOpened(
         const WebString& databaseIdentifier,
         const WebString& databaseName,
         const WebString& databaseDisplayName,
         unsigned long estimatedSize) = 0;
     virtual void databaseModified(
         const WebString& databaseIdentifier,
         const WebString& databaseName) = 0;
     virtual void databaseClosed(
         const WebString& databaseIdentifier,
@@ skipping 28 matching lines @@
         const WebString& databaseName,
         bool isSyncDatabase, int sqliteErrorCode) { }
 
 protected:
     ~WebDatabaseObserver() { }
 };
 
 } // namespace blink
 
 #endif // WebDatabaseObserver_h