GPU_Tests: Remove expectations after rebaseline

Bug: 879379
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I43e957955103e5b2d6e4ae80b296655f1b2aa5b1
Reviewed-on: https://chromium-review.googlesource.com/c/1277953Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Yi Xu <yiyix@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599121}

content/test/gpu/gpu_tests/pixel_expectations.py

@@ -138,6 +138,3 @@ class PixelExpectations(GpuTestExpectations):
         ['android', ('qualcomm', 'Adreno (TM) 420')], bug=883500)
     self.Fail('Pixel_BackgroundImage',
         ['android', ('qualcomm', 'Adreno (TM) 430')], bug=883500)
-
-    # TODO(yiyix): remove expectation after rebaseline.
-    self.Fail("Pixel_CSS3DBlueBox", bug=879379)