net: Notify the http job and cache transaction about a filter

net/url_request/url_request_job.h

Index: net/url_request/url_request_job.h
===================================================================
--- net/url_request/url_request_job.h	(revision 95711)
+++ net/url_request/url_request_job.h	(working copy)
@@ -246,6 +246,10 @@
   // info.
   virtual bool ReadRawData(IOBuffer* buf, int buf_size, int *bytes_read);
 
+  // Called to tell the job that a filter has successfully reached the end of
+  // the stream.
+  virtual void DoneReading();
+
   // Informs the filter that data has been read into its buffer
   void FilteredDataRead(int bytes_read);