cryptohome: Eliminate users of MockCryptohomeLibrary::GetSystemSalt

It seems all usage of MockCryptohomeLibrary::GetSystemSalt can be replaced with CryptohomeLibraryStubImpl (which is automatically set up by CryptohomeLibrary::Initialize for tests).

BUG=298605, 141009
TEST=git try

Review URL: https://codereview.chromium.org/25722009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226835 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226835
Hide all non activatable windows during window overview.

BUG=295862
TEST=WindowSelectorTest.NonActivatableWindowsHidden
TEST=Press Ctrl+O to open a file open dialog. Push F5 key to enter overview and parent of file dialog should be hidden.

Review URL: https://codereview.chromium.org/25742002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226836 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226836