gdata: Add ability to fetch documents in a particular directory

chrome/browser/chromeos/gdata/gdata_documents_service.h

Index: chrome/browser/chromeos/gdata/gdata_documents_service.h
diff --git a/chrome/browser/chromeos/gdata/gdata_documents_service.h b/chrome/browser/chromeos/gdata/gdata_documents_service.h
index ea41f60a712c3d9b4d7f649c9c0d58284ea434ef..20a71c80c2e034b74dc3e27fb0d7f48ae9619ea1 100644
--- a/chrome/browser/chromeos/gdata/gdata_documents_service.h
+++ b/chrome/browser/chromeos/gdata/gdata_documents_service.h
@@ -75,13 +75,21 @@ class DocumentsServiceInterface {
   // URL is empty, the call will fetch the default root or change document feed.
   // |start_changestamp| specifies the starting point from change feeds only.
   // Value different than 0, it would trigger delta feed fetching.
+  //
   // |search_query| specifies search query to be sent to the server. It will be
   // used only if |start_changestamp| is 0. If empty string is passed,
   // |search_query| is ignored.
+  //
+  // |directory_resource_id| specifies the directory from which documents are
+  // fetched. It will be used only if |start_changestamp| is 0. If empty
+  // string is passed, |directory_resource_id| is ignored.
+  //
   // Upon completion, invokes |callback| with results on the calling thread.
+  // TODO(satorux): Refactor this function: crbug.com/128746
   virtual void GetDocuments(const GURL& feed_url,
                             int start_changestamp,
                             const std::string& search_query,
+                            const std::string& directory_resource_id,
                             const GetDataCallback& callback) = 0;
 
   // Gets the account metadata from the server using the default account
@@ -183,6 +191,7 @@ class DocumentsService
   virtual void GetDocuments(const GURL& feed_url,
                             int start_changestamp,
                             const std::string& search_query,
+                            const std::string& directory_resource_id,
                             const GetDataCallback& callback) OVERRIDE;
   virtual void GetAccountMetadata(const GetDataCallback& callback) OVERRIDE;
   virtual void DeleteDocument(const GURL& document_url,