Implement DatabaseQuotaClient's DeteleteOriginData method.

webkit/quota/quota_task.h

Index: webkit/quota/quota_task.h
===================================================================
--- webkit/quota/quota_task.h	(revision 85641)
+++ webkit/quota/quota_task.h	(working copy)
@@ -66,8 +66,9 @@
  protected:
   virtual ~QuotaThreadTask();
 
-  // Called on the target message loop.
-  virtual void RunOnTargetThread() = 0;
+  // One of the following should be overriden.

[tzik, 2011/05/23 05:30:59]

Could you add some more comment for RunOnTargetThreadAsync?

[michaeln, 2011/05/23 21:56:52]

Done.

  // One of the following Run methods should be overriden for execution
  // on the target thread.

  // A task to invoke the CallCompleted() method on the original thread will
  // be scheduled immediately upon return from RunOnTargetThread().
  virtual void RunOnTargetThread();

  // A task to invoke the CallCompleted() method on the original thread will
  // only be scheduled if RunOnTargetThreadAsync returns true. If false is
  // returned, the derived class should schedule a task to do so upon actual
  // completion.
  virtual bool RunOnTargetThreadAsync();

+  virtual void RunOnTargetThread();
+  virtual bool RunOnTargetThreadAsync();
 
   virtual void Run() OVERRIDE;
   scoped_refptr<base::MessageLoopProxy> target_message_loop() const {