Avoid possible memory leaks by ensuring stream closures

Stream close() methods should always be called in finally block
to ensure we don't accidentally leak a stream.

Time to fix some old sloppy code.

Patch Set 2:
 + ensure closure of some other streams
Patch Set 3:
 + missing import java.io.IOException
Patch Set 4:
 + missing import
Patch Set 5:
 + missing ';'
 + whitespace cleanup
Patch Set 6:
 - Reverted changes to MemoryUsage (final requirement
     prevents my implentation)
 + fixed Object allocation in Root.java
Patch Set 7:
 + fixed curly bracket style violations
Patch Set 8:
 x fixed my own sloppy code :/

Change-Id: I3460b558ed5b4489296388c9a52fbb773cefd31f
GlobalActions: Fix possible race condition when showing dialog.

Depending on the presence of a previous dialog, the newly generated one
gets either immediately displayed (no old dialog) or shortly delayed
(after dismissal of the existing one).
If a new show event happens (by rapid fire of the power key, for instance,
using a keyboard with fast-repeating events) during that delay, a new
dialog will be immediately displayed, and when the delayed show triggers
it'll conflict with it (and bring everything down).

This moves the creation of the new Dialog object to _before_ showing
it (delayed or not), instead of the show method itself, to ensure the
object isn't clobbered by competing/sequential calls to handleShow()

Change-Id: Ie4d9a8507ebaf59da31869c38b98c3c98a74468e