Suppress two flaky XFB tests on ANGLE/GL.

The failure expectations are restored for two of the three new
tests. Marking as flaky - if they continue to fail despite the
flaky suppression we will need to mark them as failing.

Bug: 696345
Bug: 818383
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: I8ac5db7e2c75f2c50cbea42523767336e5c431ea
Tbr: geofflang@chromium.org
Tbr: jdarpinian@chromium.org
Tbr: kbr@chromium.org
No-try: True
Reviewed-on: https://chromium-review.googlesource.com/1010770Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550263}

content/test/gpu/gpu_tests/webgl2_conformance_expectations.py

@@ -425,6 +425,12 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
     self.Fail('deqp/functional/gles3/integerstatequery.html',
         ['passthrough', 'opengl'], bug=602688)
 
+    # These Transform Feedback tests seem flaky on ANGLE/GL.
+    self.Flaky('conformance2/transform_feedback/switching-objects.html',
+        ['passthrough', 'opengl'], bug=696345)
+    self.Flaky('conformance2/transform_feedback/too-small-buffers.html',
+        ['passthrough', 'opengl'], bug=818383)
+
     # Passthrough command decoder / OpenGL / Intel
     self.Fail('conformance2/textures/video/tex-2d-rgb32f-rgb-float.html',
         ['passthrough', 'opengl', 'intel'], bug=602688)
@@ -751,7 +757,7 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
         'random_separate_triangles.html',
         ['mac', 'amd'], bug=483282)
     self.Fail('conformance2/transform_feedback/too-small-buffers.html',
-        ['mac', 'amd', 'sierra'], bug=818383)
+        ['mac', 'amd', 'sierra', 'no_angle'], bug=818383)
 
     self.Flaky('deqp/functional/gles3/shaderindexing/mat_00.html',
         ['mac', 'amd'], bug=751254)