Add a --pause-after-load flag for debugging.

Add a --pause-after-load flag for debugging.

Currently this only support windowed browsers and the runner can only be
unpaused from the command line.

See #294

R=kevmoo@google.com

Committed: https://github.com/dart-lang/test/commit/653ef174e456b4e49b1c09de2905bc078b94ad47

[kevmoo, 2015-07-23 20:47:03]

lgtm

https://codereview.chromium.org/1248073003/diff/1/lib/src/backend/live_test_c...
File lib/src/backend/live_test_controller.dart (right):

https://codereview.chromium.org/1248073003/diff/1/lib/src/backend/live_test_c...
lib/src/backend/live_test_controller.dart:155: if
(_onPrintController.hasListener) {
what's a case where the controller has no listener?

[nweiz, 2015-07-23 21:23:00]

https://codereview.chromium.org/1248073003/diff/1/lib/src/backend/live_test_c...
File lib/src/backend/live_test_controller.dart (right):

https://codereview.chromium.org/1248073003/diff/1/lib/src/backend/live_test_c...
lib/src/backend/live_test_controller.dart:155: if
(_onPrintController.hasListener) {
On 2015/07/23 20:47:03, kevmoo wrote:
> what's a case where the controller has no listener?

After the test package has received a signal, it will unsubscribe everything,
but we may still want to see prints for debugging purposes.

[nweiz, 2015-07-23 21:24:47]

Committed patchset #1 (id:1) manually as
653ef174e456b4e49b1c09de2905bc078b94ad47 (presubmit successful).