GitLab

This CL removes a number of functions from the sync debugging framework
in order to prepare for some upcoming changes to sync debugging (due to
328606).

This CL removes the following functions:
- GetRootNodeDetails
- GetNodeSummaries
- GetNodeDetails
- GetChildNodeIds

It also adds the function 'getListOfKnownTypes' to help replace some old
functionality required by the 'data' tab and to fix issue 329013.
Rather than having that tab fetch a list of children of the root node,
it now asks for a list of all known data types.  This is a better
solution, since it does not require sync to be fully initialized in
order to properly populate the set of checkboxes.

The most significant user of the removed functionality is the node
browser.  Its javascript code has been modified in order to transition
it to relying on the getAllNodes function.  Rather than fetching node
data on demand by a series of asynchronous callbacks, the tab now
fetches a list of all known sync nodes at once.  This has the advantage
of providing a more consistent (though more stale) snapshot.  This CL
adds a refresh button to the node browser tab in order to give users
some control over its staleness.

This change had some minor side-effects.  The node browser now relies on
items' string-based IDs rather than their metahandles when determining
the nodes' hierarchy.  We've also had to add a 'positionIndex' field to
the output of getAllNodes to make it easier for the node browser to sort
its entries.  In part to make it easier to fetch this field, most of the
code associated with getAllNodes has been moved into the
syncable::Directory.

In addition to all these changes, this CL adds some webui tests to help
prevent regressions in about:sync functionality.  For now, they only
cover the node browser.  More tests will be added in future CLs.

BUG=110517,329013,328606

Review URL: https://codereview.chromium.org/134443004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245313 0039d316-1c4b-4281-b951-d872f2087c98