sync: Move unique_client_tag hashing code

sync: Move unique_client_tag hashing code

This is one of many changes that will lead up to the introduction of
the bookmark UniquePosition algorithm.

We eventually want to use the hashing code to create a unique tag for
bookmarks.  This tag will be initialized at bookmark creation time in
MutableEntry.  This patch moves the hashing code out of BaseNode and
into syncable_util so it can be accessed from the syncable layer.

BUG=145412, 126505
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=174449

[rlarocque, 2012-12-20 23:34:15]

This patch is a small independent part of
https://codereview.chromium.org/11636006/.

Please review.

[tim (not reviewing), 2012-12-21 17:26:31]

https://chromiumcodereview.appspot.com/11571092/diff/1/sync/internal_api/sync...
File sync/internal_api/sync_manager_impl_unittest.cc (right):

https://chromiumcodereview.appspot.com/11571092/diff/1/sync/internal_api/sync...
sync/internal_api/sync_manager_impl_unittest.cc:292:
syncable::GenerateSyncableHash(THEMES, "tag2"));
This looks like it should be moved to syncable_util_unittest now? 

Also I'm missing why you switched these from BOOKMARKS to THEMES?

[rlarocque, 2012-12-21 18:39:48]

Patch updated.  PTAL.

https://chromiumcodereview.appspot.com/11571092/diff/1/sync/internal_api/sync...
File sync/internal_api/sync_manager_impl_unittest.cc (right):

https://chromiumcodereview.appspot.com/11571092/diff/1/sync/internal_api/sync...
sync/internal_api/sync_manager_impl_unittest.cc:292:
syncable::GenerateSyncableHash(THEMES, "tag2"));
On 2012/12/21 17:26:31, timsteele wrote:
> This looks like it should be moved to syncable_util_unittest now? 

Good idea.  That file didn't exist before, but it's about time we created one. 
Maybe some of the tests in syncable_unittest could eventually be moved to
syncable_util_unittest.  I've populated it with just this test for now.

> 
> Also I'm missing why you switched these from BOOKMARKS to THEMES?

That was an over-agressive find and replace in the original patch set.  I was
trying to remove tests that created things that didn't occur in practice, like
bookmarks with unique client tags.  I've reverted that change.

[tim (not reviewing), 2012-12-21 18:44:45]

LGTM!

[commit-bot: I haz the power, 2012-12-21 18:45:21]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rlarocque@chromium.org/11571092/5001

[commit-bot: I haz the power, 2012-12-21 20:54:30]

Change committed as 174449