GitLab

Standalone functions replaced with InputDeviceSettings interface and
singleton implementation InputDeviceSettingsImpl.
Changing of input device settings became more efficient for two reasons:
1) InputDeviceSettingsImpl caches previously set values and doesn't
call tpcontrol/mousecontrol if client tries to set same values twice.
2) New methods for changing several settings at a time was implemented. For
example, If client wants to change several touchpad settings at a time,
he can use UpdateTouchpadSettings method that will result in one (or
zero) invocation of tpcontrol.

Implemented FakeInputDeviceSettings for use in tests.

These changes are needed for upcoming changes in chromeos::Preferences.

BUG=325564
TEST=manually
TBR=scheib

Review URL: https://codereview.chromium.org/147133003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251399 0039d316-1c4b-4281-b951-d872f2087c98