gdata: Fix a bug that caused google drive not to load

gdata: Fix a bug that caused google drive not to load

There were two subtle changes in how we stored the file system metadata
in a proto file, and each change broke compatibility in a subtle way.
We should discard the proto file if old formats are detected.

Note that the protobuf definitions in gdata.proto were kept compatible.
The problem was in how we stored data in the protobuf, and the changes were
subtle.

BUG=128133
TEST=confirmed that the google drive loaded with the stale GCache directory from josh

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=137492

[achuithb, 2012-05-16 18:25:16]

http://codereview.chromium.org/10384204/diff/1/chrome/browser/chromeos/gdata/...
File chrome/browser/chromeos/gdata/gdata_files.cc (right):

http://codereview.chromium.org/10384204/diff/1/chrome/browser/chromeos/gdata/...
chrome/browser/chromeos/gdata/gdata_files.cc:869: // The title field for the
root directory was originally empty, then
Do you think we should we plan to delete this code after a milestone or two?

[satorux1, 2012-05-16 18:28:14]

http://codereview.chromium.org/10384204/diff/1/chrome/browser/chromeos/gdata/...
File chrome/browser/chromeos/gdata/gdata_files.cc (right):

http://codereview.chromium.org/10384204/diff/1/chrome/browser/chromeos/gdata/...
chrome/browser/chromeos/gdata/gdata_files.cc:869: // The title field for the
root directory was originally empty, then
On 2012/05/16 18:25:17, achuith.bhandarkar wrote:
> Do you think we should we plan to delete this code after a milestone or two?

I think the code here will be deleted anyway once we migrate to your metadata
storage?

[achuithb, 2012-05-16 18:31:36]

lgtm

[achuithb, 2012-05-16 18:32:13]

On 2012/05/16 18:31:36, achuith.bhandarkar wrote:
> lgtm

Thanks for the fix. I think I inadvertently introduced the bug.