Search for privet destinations only once

In print preview, do not search for privet destinations every time the destination search button is clicked. This should stop the throbber from appearing every time you go to choose the destination.

BUG=326101

Review URL: https://codereview.chromium.org/102473006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239050 0039d316-1c4b-4281-b951-d872f2087c98
For Privet printing, cache the capabilities and use them to generate the preview

Use cached capabilities to generate the preview for privet printing until
printer is found.

BUG=325983

Review URL: https://codereview.chromium.org/102693006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239052 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239052
Rename the X-Chrome-Variations header to X-Client-Data.

BUG=325472

Review URL: https://codereview.chromium.org/103063002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239054 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239054
Disable TabCaptureApiTest.CaptureInSplitIncognitoMode on Mac because of flakiness.

BUG=326319
TBR=justinlin

Review URL: https://codereview.chromium.org/106903006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239055 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239055