Adding failure expectation for failing tests:

 - virtual/gpu-rasterization/images/color-profile-clip.html
 - virtual/gpu-rasterization/images/color-profile-munsell-adobe-to-srgb.html
 - virtual/gpu-rasterization/images/color-profile-munsell-srgb-to-srgb.html

BUG=791941
NOTRY=true

Change-Id: Id70d34e000a38280738b7937d108c082ad8d56ab
Reviewed-on: https://chromium-review.googlesource.com/807932Reviewed-by: Mike West <mkwst@chromium.org>
Commit-Queue: Markus Heintz <markusheintz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521655}

third_party/WebKit/LayoutTests/TestExpectations

@@ -3663,6 +3663,11 @@ crbug.com/790025 virtual/gpu-rasterization/images/image-hover-display-alt.html [
 # Sheriff failures 2017-12-04
 crbug.com/667560 http/tests/devtools/elements/styles-4/inline-style-sourcemap.js [ Pass Failure ]
 
+# Sheriff failures 2017-12-05
+crbug.com/791941 [ Mac ] virtual/gpu-rasterization/images/color-profile-clip.html [ Pass Failure ]
+crbug.com/791941 [ Mac ] virtual/gpu-rasterization/images/color-profile-munsell-adobe-to-srgb.html [ Pass Failure ]
+crbug.com/791941 [ Mac ] virtual/gpu-rasterization/images/color-profile-munsell-srgb-to-srgb.html [ Pass Failure ]
+
 # These tests fail often on Linux. https://crbug.com/790549
 crbug.com/788390 [ Linux ] http/tests/media/autoplay/document-user-activation-cross-origin-feature-policy-delegation.html [ Failure Pass Timeout ]
 crbug.com/788390 [ Linux ] http/tests/media/autoplay/document-user-activation-cross-origin-feature-policy-disabled.html [ Failure Pass Timeout ]