Do not register non-persistent crostini shared paths

We can't be sure at any given time that the VM has not
restarted and that a non-persistent share is still shared.
So we will not register them as shared.  If we happen to
take an action on the file more than once, there is little
harm to (re)attempt to share the path.

Bug: 925973
Change-Id: Ie3a4b4a3009c5846cd31754c2b642f2a369cebb4
Reviewed-on: https://chromium-review.googlesource.com/c/1481183
Auto-Submit: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Stuart Langley <slangley@chromium.org>
Reviewed-by: Stuart Langley <slangley@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634441}

ui/file_manager/file_manager/foreground/js/file_tasks.js

@@ -687,10 +687,9 @@ FileTasks.prototype.maybeShareWithCrostiniOrShowDialog_ = function(
               'Error sharing with linux to execute: ' +
               chrome.runtime.lastError.message);
         }
-        // Register paths as shared, and now we are ready to execute.
-        entriesToShare.forEach((entry) => {
-          this.crostini_.registerSharedPath(entry);
-        });
+        // crbug.com/925973.  Do not register non-persisted shared paths since
+        // we can't be sure at any time that the VM has not restarted and they
+        // are still shared.
         callback();
       });
 };

ui/file_manager/file_manager/foreground/js/file_tasks_unittest.js

@@ -636,6 +636,8 @@ function testMaybeShareCrostiniOrShowDialog() {
   expect(
       '2 entries, not shared, same dir', [notShared1, notShared2], true, '',
       '');
+  // Non-persistent shares should not be registered.
+  assertFalse(crostini.isPathShared(notShared1));
 
   expect(
       '2 entries, not shared, different dir', [notShared1, otherNotShared],