Make GPU Rasterization Default on Windows

Wrapping up finch roll-out by making this default and switching to a
10% finch hold-back group in Canary.

R=vmiura@chromium.org
BUG=643850
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2844483003
Cr-Original-Commit-Position: refs/heads/master@{#467198}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 4166ab857753a66e9ba6aea475ada0f14b0971d8
1 file changed