Mark depthStreamToRGBAUint8Texture Flaky on HighSierra AMD

BUG=819661
TBR=kbr@chromium.org

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
Change-Id: If9d0357866a390ad88cf049ebb76f80588dfe0b2
Reviewed-on: https://chromium-review.googlesource.com/953073
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541521}

content/test/gpu/gpu_tests/depth_capture_expectations.py

@@ -17,5 +17,7 @@ class DepthCaptureExpectations(GpuTestExpectations):
                ['linux', ('nvidia', 0x104a)], bug=737410)
     self.Flaky('DepthCapture_depthStreamToRGBAUint8Texture',
                ['linux', ('nvidia', 0x104a)], bug=737410)
+    self.Flaky('DepthCapture_depthStreamToRGBAUint8Texture',
+               ['highsierra', ('amd', 0x6821)], bug=819661)
     self.Fail('DepthCapture_depthStreamToR32FloatTexture',
               ['android', ('qualcomm', 'Adreno (TM) 330')], bug=765913)