Adding a not explicit source makes it explicit.

Adding a not explicit source makes it explicit.

When we add a new file in IDEA and open it in the editor, this causes
analysis.setSubscriptions to be send immediately, even before watcher
notices it. The server reacts by requesting the fully resolved unit, and
so causes creation of a not-explicit CacheEntry. So, when later we handle
applyChanges(), the entry already exists. In this case we still need to
mark it as explicit.

R=brianwilkerson@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/1bc7f930091ed6534d83526c6fd0d75c90e2ebb6

[Brian Wilkerson, 2015-10-30 13:54:24]

LGTM

[scheglov, 2015-10-30 15:04:34]

Committed patchset #1 (id:1) manually as
1bc7f930091ed6534d83526c6fd0d75c90e2ebb6 (presubmit successful).