Offload disk accesses to WorkerPool in ExtensionProtocolHandler

net/url_request/url_request_data_job.h

Index: net/url_request/url_request_data_job.h
===================================================================
--- net/url_request/url_request_data_job.h	(revision 147715)
+++ net/url_request/url_request_data_job.h	(working copy)
@@ -21,9 +21,10 @@
   static URLRequest::ProtocolFactory Factory;
 
   // URLRequestSimpleJob
-  virtual bool GetData(std::string* mime_type,
-                       std::string* charset,
-                       std::string* data) const OVERRIDE;
+  virtual int GetData(std::string* mime_type,
+                      std::string* charset,
+                      std::string* data,
+                      const CompletionCallback& callback) const OVERRIDE;
 
  private:
   virtual ~URLRequestDataJob();