GitLab

Turning off the internal display while an external one is connected will
enter the device into docked mode, and will exit the maximized mode (if any).
We need to make sure that the keyboard and touchpad events are re-enabled
when the maximize mode exits.

BUG=549803
TEST=ash_unittests --gtest_filter=MaximizeModeControllerTest.NoMaximizeModeWithDisabledInternalDisplay

Review URL: https://codereview.chromium.org/1588883005

Cr-Commit-Position: refs/heads/master@{#370436}