Debugger: remove dead feature (SkPicture offset display) & fix bug (unbalanced indents)

Displaying the offset into an SkPicture hasn't worked for a while so this CL deletes the feature.
When "Save Layer" was renamed to "SaveLayer" the code that computes the indent in the list view was broken. This CL patches the problem.

Review URL: https://codereview.chromium.org/1034733004
8 files changed