gdata: Convert FindEntryByResourceIdSync() to asynchronous.

chrome/browser/chromeos/gdata/gdata_params.h

Index: chrome/browser/chromeos/gdata/gdata_params.h
diff --git a/chrome/browser/chromeos/gdata/gdata_params.h b/chrome/browser/chromeos/gdata/gdata_params.h
index 58dacc7d180f3e64d95301bb2bae5684a705b15d..93d9ae343a78a8a95f8eae6cc38ea7397a97aae3 100644
--- a/chrome/browser/chromeos/gdata/gdata_params.h
+++ b/chrome/browser/chromeos/gdata/gdata_params.h
@@ -15,6 +15,7 @@
 #include "base/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/platform_file.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/gdata/gdata_parser.h"
 #include "net/base/io_buffer.h"
@@ -22,6 +23,8 @@
 
 namespace gdata {
 
+class GDataEntry;
+
 // Struct for response to ResumeUpload.
 struct ResumeUploadResponse {
   ResumeUploadResponse(GDataErrorCode code,
@@ -111,6 +114,11 @@ typedef base::Callback<void(
     const ResumeUploadResponse& response,
     scoped_ptr<gdata::DocumentEntry> new_entry)> ResumeUploadCallback;
 
+// Callback type used to get result of file search.
+// If |error| is not PLATFORM_FILE_OK, |entry| is set to NULL.
+typedef base::Callback<void(base::PlatformFileError error, GDataEntry* entry)>
+    FindEntryCallback;
+
 }  // namespace gdata
 
 #endif  // CHROME_BROWSER_CHROMEOS_GDATA_GDATA_PARAMS_H_