Make FileSystemOperation's lifetime more explicit.

webkit/fileapi/file_system_operation.h

Index: webkit/fileapi/file_system_operation.h
diff --git a/webkit/fileapi/file_system_operation.h b/webkit/fileapi/file_system_operation.h
index 01e2da1853c6dbeba2f55494a71137b6ee7f9b27..09392b498e8d13c22ba12e6cd803d0133431dc7c 100644
--- a/webkit/fileapi/file_system_operation.h
+++ b/webkit/fileapi/file_system_operation.h
@@ -33,8 +33,11 @@ class FileWriterDelegate;
 // Only one method(CreateFile, CreateDirectory, Copy, Move, DirectoryExists,
 // GetMetadata, ReadDirectory and Remove) may be called during the lifetime of
 // this object and it should be called no more than once.
+// This class is self-destructed and an instance automatically gets deleted
+// when its operation is finished.
 class FileSystemOperation {
  public:
+  // |dispatcher| will be owned by this class.
   FileSystemOperation(FileSystemCallbackDispatcher* dispatcher,
                       scoped_refptr<base::MessageLoopProxy> proxy);
   virtual ~FileSystemOperation();
@@ -62,15 +65,16 @@ class FileSystemOperation {
 
   virtual void Remove(const FilePath& path, bool recursive);
 
-  virtual void Write(
-      scoped_refptr<URLRequestContext> url_request_context,
-      const FilePath& path, const GURL& blob_url, int64 offset);
+  virtual void Write(scoped_refptr<URLRequestContext> url_request_context,
+                     const FilePath& path,
+                     const GURL& blob_url,
+                     int64 offset);
 
   virtual void Truncate(const FilePath& path, int64 length);
 
   virtual void TouchFile(const FilePath& path,
-                 const base::Time& last_access_time,
-                 const base::Time& last_modified_time);
+                         const base::Time& last_access_time,
+                         const base::Time& last_modified_time);
 
   // Try to cancel the current operation [we support cancelling write or
   // truncate only].  Report failure for the current operation, then tell the
@@ -100,7 +104,15 @@ class FileSystemOperation {
   OperationType pending_operation_;
 #endif
 
-  FileSystemCallbackDispatcher* dispatcher() const { return dispatcher_.get(); }
+  // Returns a destructive dispatcher which deletes the operation instance
+  // after any of its callback methods is called (except for DidWrite with
+  // complete=false cases).
+  FileSystemCallbackDispatcher* destructive_dispatcher() const {
+    return destructive_dispatcher_.get();
+  }
+
+  // Returns a non-destructive dispatcher.
+  FileSystemCallbackDispatcher* non_destructive_dispatcher() const;
 
  private:
   // Callback for CreateFile for |exclusive|=true cases.
@@ -143,7 +155,7 @@ class FileSystemOperation {
   // Proxy for calling file_util_proxy methods.
   scoped_refptr<base::MessageLoopProxy> proxy_;
 
-  scoped_ptr<FileSystemCallbackDispatcher> dispatcher_;
+  scoped_ptr<FileSystemCallbackDispatcher> destructive_dispatcher_;
 
   base::ScopedCallbackFactory<FileSystemOperation> callback_factory_;