[Telemetry] Fail fast if Browser goes away during launch

In the case of an error launching Chrome, Telemetry will hang for 30 seconds waiting for Chrome to reply on the socket before it realizes the browser has gone away.

This CL adds a call to .poll() in ChromeBrowserBackend._WaitForBrowserToComeUp() which will throw an exception if Chrome goes away on launch so Telemetry can exit instantly.

BUG=None

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=249045

Review URL: https://codereview.chromium.org/138663008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250015 0039d316-1c4b-4281-b951-d872f2087c98
[Telemetry] Add idle process metrics on OS X > 10.8.4 .

BUG=338712

Review URL: https://codereview.chromium.org/143823019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250016 0039d316-1c4b-4281-b951-d872f2087c98
Add key based scrolling on magnified screen for kiosk mode.

* Add MagnifierKeyScroller event handler that interprets
  click and hold action.
* kAshEnableMagnifierKeyScroller to test on desktop.
* Modified EventGenerator to generate native event for key press/release.

BUG=340729
TEST=MagnifierKeyScrollerTest

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=249996

Review URL: https://codereview.chromium.org/155493002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250017 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250017
Fallback to CDD/CJT if connector can't initialize XPS API.

BUG=313274

Review URL: https://codereview.chromium.org/147953009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250018 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250018