Mark Mac NVIDIA Retina 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 6185f4e7b7f5518cec826ee32b096ff4f5583d18..119d9c6373f7ca9225e9f5ec85b6e46b251a768d 100644
--- a/content/test/gpu/gpu_tests/webgl2_conformance_expectations.py
+++ b/content/test/gpu/gpu_tests/webgl2_conformance_expectations.py
@@ -219,6 +219,9 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
         ['mac', ('nvidia', 0xfe9)], bug=483282)
     self.Fail('conformance2/textures/misc/tex-input-validation.html',
         ['mac', ('nvidia', 0xfe9), 'no_angle'], bug=483282)
+    self.Flaky('conformance2/textures/image_bitmap_from_video/' +
+        'tex-2d-rgba16f-rgba-half_float.html',
+        ['mac', ('nvidia', 0xfe9)], bug=682834)
 
     self.Fail('deqp/functional/gles3/framebufferblit/conversion_04.html',
         ['mac', ('nvidia', 0xfe9)], bug=483282)