Removes GCRoots pane

This change pulls out the action that triggered dominator
computation from the GCRoots class into its own class.

Changes the action from Toggle to AnAction and moved the
execution to the performAction instead of the update method.

Merges the indicator and the runnable in the same class.

Change-Id: Ic7d8c6468bbf23434238a13be6c8a7db587534c7
5 files changed