Fix conversion between virtual paths and URLs.

The URLs encode space as %20, while virtual paths should use a space character. This caused failures in resolving shortcuts created by new version of Chrome, on older chromebooks, what was causing removing these shortcuts.

TEST=Tested manually the scenario above.
BUG=336155

Review URL: https://codereview.chromium.org/151233002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248158 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248158