Mark webgl2 conformance test as flaky

content/test/gpu/gpu_tests/webgl2_conformance_expectations.py

Index: content/test/gpu/gpu_tests/webgl2_conformance_expectations.py
diff --git a/content/test/gpu/gpu_tests/webgl2_conformance_expectations.py b/content/test/gpu/gpu_tests/webgl2_conformance_expectations.py
index bc5faa1552d5a29bef0648e1dd4aa0d34d8e78d9..0f83ebef076157a29ccd19f762ba99eae1ab9703 100644
--- a/content/test/gpu/gpu_tests/webgl2_conformance_expectations.py
+++ b/content/test/gpu/gpu_tests/webgl2_conformance_expectations.py
@@ -126,6 +126,8 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
         '-with-webgl-canvas-rgba4-rgba-unsigned_short_4_4_4_4.html',
         ['win'], bug=483282)
 
+    self.Flaky('deqp/functional/gles3/buffercopy.html', ['win'], bug=587601)
+
     self.Skip('deqp/functional/gles3/readpixel.html', ['win'], bug=483282)
     self.Skip('deqp/functional/gles3/texturestatequery.html',
         ['win'], bug=483282)