gdata: Convert FindEntryByResourceIdSync() to asynchronous.

chrome/browser/chromeos/gdata/gdata_files.h

Index: chrome/browser/chromeos/gdata/gdata_files.h
diff --git a/chrome/browser/chromeos/gdata/gdata_files.h b/chrome/browser/chromeos/gdata/gdata_files.h
index bc6f7f7897a57e62c21cf6bacbd3e076c84dd7c2..538169017667e5ddd8a447436102605b75e3f52e 100644
--- a/chrome/browser/chromeos/gdata/gdata_files.h
+++ b/chrome/browser/chromeos/gdata/gdata_files.h
@@ -17,7 +17,6 @@
 #include "base/memory/weak_ptr.h"
 #include "base/platform_file.h"
 #include "base/synchronization/lock.h"
-#include "chrome/browser/chromeos/gdata/find_entry_callback.h"
 #include "chrome/browser/chromeos/gdata/gdata_params.h"
 #include "chrome/browser/chromeos/gdata/gdata_parser.h"
 #include "chrome/browser/chromeos/gdata/gdata_uploader.h"
@@ -26,6 +25,7 @@
 
 namespace gdata {
 
+class GDataEntry;
 class GDataFile;
 class GDataDirectory;
 class GDataRootDirectory;
@@ -64,6 +64,16 @@ const FilePath::CharType kGDataRootDirectory[] = FILE_PATH_LITERAL("drive");
 // https://developers.google.com/google-apps/documents-list/
 const char kGDataRootDirectoryResourceId[] = "folder:root";
 
+// 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;
+
+// Callback used to find a directory element for file system updates.
+void ReadOnlyFindEntryCallback(GDataEntry** out,

[hashimoto, 2012/06/11 09:44:34]

This function looks only used by GDataFileSystem::GetGDataEntryPath and
GDataFileSystemTest::FindEntry (and the two are looking almost same)
Can you make this function only visible from within gdata_file_system.cc?
(This can be postponed to a later patch)

[hshi1, 2012/06/11 17:48:53]

I'm moving this to gdata_file_system.cc, but it needs to be visible to
gdata_file_system_unittest.cc also.

[achuithb, 2012/06/11 20:46:37]

I'm not sure why you got rid of find_entry_callback.h/.cc?

[hshi1, 2012/06/11 20:58:51]

IMHO the definition of FindEntryCallback type and the ReadOnlyFindEntryCallback
function are too simple to deserve their own header and .cc files, plus it seems
unlikely that these two files would be expanded much further.

[achuithb, 2012/06/11 21:48:41]

Yes, but the new locations for FindEntryCallback and ReadOnlyFileEntryCallback
seem pretty random. FindEntryCallback is used both in gdata_file_system.h and
gdata_files.h, right? gdata_files.* is not as bad as gdata_file_system.* but
it's also big and doesn't need to get bigger with unrelated items. How about
moving it to gdata_params.h? 

[achuithb, 2012/06/12 07:59:47]

This didn't get addressed. gdata_params.h was designed to be a light-weight
place to put typedefs such as this, so you wouldn't need to include
gdata_files.h to get the definition of FindEntryCallback.

+                               base::PlatformFileError error,
+                               GDataEntry* entry);
+
 // Base class for representing files and directories in gdata virtual file
 // system.
 class GDataEntry {