net: Implement canceling of all async operations in FileStream.

net/base/file_stream_posix.h

Index: net/base/file_stream_posix.h
===================================================================
--- net/base/file_stream_posix.h	(revision 147715)
+++ net/base/file_stream_posix.h	(working copy)
@@ -7,8 +7,6 @@
 #ifndef NET_BASE_FILE_STREAM_POSIX_H_
 #define NET_BASE_FILE_STREAM_POSIX_H_
 
-#include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
 #include "base/platform_file.h"
 #include "net/base/completion_callback.h"
 #include "net/base/file_stream_whence.h"
@@ -54,25 +52,18 @@
       const net::BoundNetLog& owner_bound_net_log);
   base::PlatformFile GetPlatformFileForTesting();
 
-  // Resets on_io_complete_ and WeakPtr's.
-  // Called when Read() or Write() is completed.
-  void ResetOnIOComplete();
-
  private:
-  // Called when the file_ is closed asynchronously.
-  void OnClosed(const CompletionCallback& callback);
+  class AsyncContext;
 
-  // Waits until the in-flight async open/close/read/write operation is
-  // complete.
-  void WaitForIOCompletion();
+  bool is_async() { return !!(open_flags_ & base::PLATFORM_FILE_ASYNC); }
 
-  base::PlatformFile file_;
+  // Context performing I/O operations. Despite its name the context is used
+  // for synchronous operations too, but it was extracted into separate class
+  // to perform asynchronous operations correctly.
+  AsyncContext* context_;
+
   int open_flags_;
-  bool auto_closed_;
-  bool record_uma_;
   net::BoundNetLog bound_net_log_;
-  base::WeakPtrFactory<FileStreamPosix> weak_ptr_factory_;
-  scoped_ptr<base::WaitableEvent> on_io_complete_;
 
   DISALLOW_COPY_AND_ASSIGN(FileStreamPosix);
 };