Disk cache: Switch the disk cache to use the cache_thread....

net/disk_cache/entry_impl.h

Index: net/disk_cache/entry_impl.h
===================================================================
--- net/disk_cache/entry_impl.h	(revision 50158)
+++ net/disk_cache/entry_impl.h	(working copy)
@@ -53,6 +53,20 @@
   virtual void CancelSparseIO();
   virtual int ReadyForSparseIO(net::CompletionCallback* completion_callback);
 
+  // Background implementation of the Entry interface.
+  void DoomImpl();
+  int ReadDataImpl(int index, int offset, net::IOBuffer* buf, int buf_len,
+                   CompletionCallback* callback);
+  int WriteDataImpl(int index, int offset, net::IOBuffer* buf, int buf_len,
+                    CompletionCallback* callback, bool truncate);
+  int ReadSparseDataImpl(int64 offset, net::IOBuffer* buf, int buf_len,
+                         CompletionCallback* callback);
+  int WriteSparseDataImpl(int64 offset, net::IOBuffer* buf, int buf_len,
+                          CompletionCallback* callback);
+  int GetAvailableRangeImpl(int64 offset, int len, int64* start);
+  void CancelSparseIOImpl();
+  int ReadyForSparseIOImpl(CompletionCallback* callback);
+
   inline CacheEntryBlock* entry() {
     return &entry_;
   }
@@ -186,8 +200,7 @@
   scoped_array<char> user_buffers_[kNumStreams];  // Store user data.
   // Files to store external user data and key.
   scoped_refptr<File> files_[kNumStreams + 1];
-  // Copy of the file used to store the key. We don't own this object.
-  mutable File* key_file_;
+  mutable std::string key_;           // Copy of the key.
   int unreported_size_[kNumStreams];  // Bytes not reported yet to the backend.
   bool doomed_;               // True if this entry was removed from the cache.
   scoped_ptr<SparseControl> sparse_;  // Support for sparse entries.