Add GetChangelist operation for Drive V2.

chrome/browser/chromeos/gdata/drive_api_operations.h

 // Copyright (c) 2012 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 CHROME_BROWSER_CHROMEOS_GDATA_DRIVE_API_OPERATIONS_H_
 #define CHROME_BROWSER_CHROMEOS_GDATA_DRIVE_API_OPERATIONS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 29 matching lines @@
   virtual ~GetApplistOperation();
 
  protected:
   // Overridden from GetDataOperation.
   virtual GURL GetURL() const OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GetApplistOperation);
 };
 
+//============================ GetChangelistOperation ==========================
+
+// This class performs the operation for fetching changelist.
+class GetChangelistOperation : public GetDataOperation {
+ public:
+  GetChangelistOperation(GDataOperationRegistry* registry,

[hashimoto, 2012/08/07 07:36:57]

Please add a comment about the role of |start_changestamp|

[kochi, 2012/08/07 07:46:04]

Done.

+                         int64 start_changestamp,
+                         const GetDataCallback& callback);
+  virtual ~GetChangelistOperation();
+
+  // Sets |url| for changelist fetching operation. This should be used when it
+  // is necessary to explicitly specify the next page URL.
+  void SetURL(const GURL& url);

[hashimoto, 2012/08/07 07:36:57]

Do we need this method?
Can't |url| be passed to the ctor?

[kochi, 2012/08/07 07:46:04]

Changed the comment to be more specific.

The knowledge of what URL should be used is centralized in
drive_api_operations.cc, and the users can be ignorant about
this.  The use case for this method is that if the
changelist is too big to fit in one response, it returns
the next page URL with a token.  Then the user can pass
that URL for the next page.

If we made |url| as a ctor parameter, the user would have to
know the first request URL.

[hashimoto, 2012/08/07 07:57:43]

What I meant was deleting SetURL and allowing passing empty GURL for the ctor
like DocumentsService::GetChangelist.
I thought allowing passing empty GURL for the ctor is better than exposing a
setter as public.
What do you think?

[kochi, 2012/08/07 09:06:52]

Agreed, removed SetURL() from this file and
gdata_operations.cc.

+
+ protected:
+  // Overridden from GetDataOperation.
+  virtual GURL GetURL() const OVERRIDE;
+
+ private:
+  GURL override_url_;
+  int64 start_changestamp_;
+
+  DISALLOW_COPY_AND_ASSIGN(GetChangelistOperation);
+};
+
 }  // namespace gdata
 
 #endif  // CHROME_BROWSER_CHROMEOS_GDATA_DRIVE_API_OPERATIONS_H_