Use a more precise type for "object" in analysis server API.

Use a more precise type for "object" in analysis server API.

Previously, we translated "object" in the API to the dart type
"Object".  But this is not correct, since in the API when we say
"object" we mean "JSON object", which corresponds to a Dart Map.

Using a more precise type exposed some bugs in our refactoring
implementation, where we were forgetting to convert objects to and
from JSON.

R=scheglov@google.com

Committed: https://code.google.com/p/dart/source/detail?r=39757

[Paul Berry, 2014-09-02 16:47:44]

paulberry@google.com changed reviewers:
+ scheglov@google.com

[scheglov, 2014-09-02 16:58:58]

LGTM

[Paul Berry, 2014-09-02 17:46:08]

Committed patchset #1 manually as 39757 (presubmit successful).