Mark offscreencanvas printing layout tests as flaky on Trusty.

third_party/WebKit/LayoutTests/TestExpectations

Index: third_party/WebKit/LayoutTests/TestExpectations
diff --git a/third_party/WebKit/LayoutTests/TestExpectations b/third_party/WebKit/LayoutTests/TestExpectations
index f52b94cfeceda882e9ac65d4b710b7d43db604e7..277acc5c1c924326255b911bdd75e1f5d39ee49b 100644
--- a/third_party/WebKit/LayoutTests/TestExpectations
+++ b/third_party/WebKit/LayoutTests/TestExpectations
@@ -2229,6 +2229,10 @@ crbug.com/674466 [ Win10 ] fast/forms/select/menulist-appearance-rtl.html [ Pass
 crbug.com/674468 [ Trusty ] compositing/reflections/nested-reflection-transition.html [ Pass Failure ]
 crbug.com/674720 [ Debug Trusty ] http/tests/loading/preload-img-test.html [ Pass Failure ]
 
+# Added 2016-12-16
+crbug.com/674858 [ Trusty ] virtual/threaded/printing/offscreencanvas-2d-printing.html [ Pass Failure ]
+crbug.com/674858 [ Trusty ] virtual/threaded/printing/offscreencanvas-webgl-printing.html [ Pass Failure ]
+
 # for Skia DEPS roll
 crbug.com/674509   compositing/overlap-blending/reflection-opacity-huge.html [ NeedsRebaseline ]
 crbug.com/674509   compositing/reflections/animation-inside-reflection.html [ NeedsRebaseline ]