Reset the state of the download item view in response to losing mouse capture a during drag&drop operation.
Otherwise on Chrome OS the download item remains in a pressed state through the drag & drop operation and also thereafter.
Also fix animations during download item view state transitions. Previously on Windows an incorrectly started animation caused a brief flicker of the download item at the start of the drag operation.
BUG=152058
Review URL: https://chromiumcodereview.appspot.com/
10990071
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@159203 0039d316-1c4b-4281-b951-d872f2087c98