Improve precision of uninitialized-test-2.html suppression.

The last change caused a reliable failure on Linux AMD.

BUG=671791
CQ_INCLUDE_TRYBOTS=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;master.tryserver.chromium.android:android_optional_gpu_tests_rel
TBR=zmo@chromium.org,geofflang@chromium.org
NOTRY=true

Review-Url: https://codereview.chromium.org/2566603002
Cr-Commit-Position: refs/heads/master@{#437479}

content/test/gpu/gpu_tests/webgl2_conformance_expectations.py

@@ -43,7 +43,14 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
     # All platforms.
     self.Flaky('conformance2/query/occlusion-query.html', bug=603168)
     self.Fail('conformance2/glsl3/tricky-loop-conditions.html', bug=483282)
-    self.Flaky('conformance2/misc/uninitialized-test-2.html', bug=671791)
+
+    # This next one fails reliably on Linux AMD and is flaky everywhere
+    # else. Unfortunately, this means the expectation needs to be
+    # complicated to avoid collisions (and unit test failures).
+    self.Flaky('conformance2/misc/uninitialized-test-2.html',
+        ['win', 'mac', 'chromeos', 'android'], bug=671791)
+    self.Flaky('conformance2/misc/uninitialized-test-2.html',
+        ['linux', 'intel', 'nvidia'], bug=671791)
     self.Fail('conformance2/rendering/depth-stencil-feedback-loop.html',
         bug=660844) # WebGL 2.0.1
     self.Fail('conformance2/rendering/rendering-sampling-feedback-loop.html',
@@ -623,6 +630,8 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
     self.Fail('deqp/functional/gles3/transformfeedback/array_separate*.html',
         ['linux', 'amd'], bug=483282)
 
+    self.Fail('conformance2/misc/uninitialized-test-2.html',
+        ['linux', 'amd'], bug=483282)
     self.Fail('conformance2/rendering/blitframebuffer-filter-srgb.html',
         ['linux', 'amd'], bug=634525)
     self.Fail('conformance2/rendering/blitframebuffer-outside-readbuffer.html',