Fixed update mechanism for the file manager preview.

Fixed update mechanism for the file manager preview.

The preview pane lined to the focused item in the file list. However was updated on update selection and disappeared when the selection gets empty (it happens when the user clicks on the checkbox of a single selected item). There is a way to move focus (it's calls 'a lead item' internally) without changing selection (using ctrl+arrows).

BUG=chromium-os:18211
TEST=None


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=98985

[SeRya, 2011-08-31 12:53:24]

Please, review.

[Dmitry Zvorygin, 2011-08-31 15:07:52]

On 2011/08/31 12:53:24, SeRya wrote:
> Please, review.

LGTM

[commit-bot: I haz the power, 2011-08-31 16:39:05]

Change committed as 98985

[rginda, 2011-08-31 18:04:12]

I think this would have been a much less invasive change if we just updated the
selection when the lead item changed.

http://codereview.chromium.org/7785026/diff/6002/chrome/browser/resources/fil...
File chrome/browser/resources/file_manager/js/file_manager.js (right):

http://codereview.chromium.org/7785026/diff/6002/chrome/browser/resources/fil...
chrome/browser/resources/file_manager/js/file_manager.js:2041: } else {
else after return.

http://codereview.chromium.org/7785026/diff/6002/chrome/browser/resources/fil...
chrome/browser/resources/file_manager/js/file_manager.js:3038: var leadEntry =
this.getLeadEntry();
If you have some items selected and press enter, it's going to change directory
as long as the lead item is a directory.

We should test that selection.totalLength == 0, or that totalLength == 1 and the
selected item is the lead item, except that sounds like a mess :/