[Pepper][FileAPI] Interface clean up (3/6)

webkit/browser/fileapi/quota/open_file_handle.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WEBKIT_BROWSER_FILEAPI_QUOTA_OPEN_FILE_HANDLE_H_
 #define WEBKIT_BROWSER_FILEAPI_QUOTA_OPEN_FILE_HANDLE_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "webkit/browser/webkit_storage_browser_export.h"
 
 namespace fileapi {
 
 class QuotaReservation;
 class OpenFileHandleContext;
 class QuotaReservationBuffer;
 
 // Represents an open file like a file descriptor.
 // This should be alive while a consumer keeps a file opened and should be
 // deleted when the plugin closes the file.
 class WEBKIT_STORAGE_BROWSER_EXPORT OpenFileHandle {
  public:
   ~OpenFileHandle();
 
   // Updates cached file size and consumes quota for that.
-  // This should be called for each modified file before calling RefreshQuota
-  // and file close.
-  // Returns updated base file size that should be used to measure quota
-  // consumption by difference to this.
-  int64 UpdateMaxWrittenOffset(int64 offset);
+  // This should be called for each modified file before calling
+  // QuotaReservation::RefreshQuota and before closing the file.
+  void UpdateMaxWrittenOffset(int64 offset);
 
-  int64 base_file_size() const;
+  // Returns the estimated file size for the quota consumption calculation.
+  // The client must consume its reserved quota when it writes data to the file
+  // beyond the estimated file size.
+  // The estimated file size is greater than or equal to actual file size after
+  // all clients report their file usage,  and is monotonically increasing over
+  // OpenFileHandle object life cycle, so that client may cache the value.
+  int64 GetEstimatedFileSize() const;
 
  private:
   friend class QuotaReservationBuffer;
 
   OpenFileHandle(QuotaReservation* reservation,
                  OpenFileHandleContext* context);
 
   scoped_refptr<QuotaReservation> reservation_;
   scoped_refptr<OpenFileHandleContext> context_;
 
   base::SequenceChecker sequence_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(OpenFileHandle);
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_BROWSER_FILEAPI_QUOTA_OPEN_FILE_HANDLE_H_