Make sure activity log is turned on for whitelisted IDs; centralize this to one place so that we don't have multiple redundant checks.

BUG=319528

Review URL: https://codereview.chromium.org/105523005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240661 0039d316-1c4b-4281-b951-d872f2087c98
DevTools: Display a helpful warning with a docs link when no devices detected in chrome://inspect

BUG=326623

Review URL: https://codereview.chromium.org/109613007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240662 0039d316-1c4b-4281-b951-d872f2087c98
SyncFS: Add VerifyConsistency method to FakeRemoteChangeProcessor

Refactoring only; so that it can be used in other tests too.

BUG=none

Review URL: https://codereview.chromium.org/112513003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240663 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 240662
SVN changes up to revision 240663