Mark windows form control tests as NeedsManualRebaseline for skia roll

Once we roll skia to f73c237291bb1fc698f688d8a9b1cdd23838ed18 a bunch
of windows form tests needs to be rebaselines.

BUG=395043
R=bungeman@chromium.org

Review URL: https://codereview.chromium.org/414873003

git-svn-id: svn://svn.chromium.org/blink/trunk@178787 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Improve GN build test targets.

Add missing dependency on make_core_generated_private_script_for_testing.

Rename wtf:unittest_helpers to wtf:test_support for project consistency (I'm trying to standardize everything on "test_support").

Add blink:test_support target.

BUG=

Review URL: https://codereview.chromium.org/410083007

git-svn-id: svn://svn.chromium.org/blink/trunk@178788 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Peer::m_syncHelper should be cleared when the Peer is destroyed

This is a speculative fix for crashes in websocket tests in oilpan bots.

Peer::m_syncHelper should be cleared when the Peer object is destroyed. Otherwise, the main thread keeps retaining a Member to the on-heap SyncHelper object allocated in the worker thread's heap even after the worker thread shuts down. This is not allowed in oilpan. All references to on-heap objects on worker thread's heap should be cleared before the worker thread shuts down.

BUG=396503

Review URL: https://codereview.chromium.org/411543008

git-svn-id: svn://svn.chromium.org/blink/trunk@178789 bbb929c8-8fbe-4397-9dbb-9b2b20218538