DevTools: Do not lock device screen while the page is being inspected via remote debugging

BUG=302280

Review URL: https://codereview.chromium.org/34553002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230098 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230098