Prevent implicit framebuffer clear from clobbering alpha in emulated RGB

content/test/gpu/gpu_tests/pixel_test_pages.py

Index: content/test/gpu/gpu_tests/pixel_test_pages.py
diff --git a/content/test/gpu/gpu_tests/pixel_test_pages.py b/content/test/gpu/gpu_tests/pixel_test_pages.py
index 71895e756029acb0c9deef6a01c1efe8edd19ba0..0ed125877aa536d0081178040c10302d0a647a5a 100644
--- a/content/test/gpu/gpu_tests/pixel_test_pages.py
+++ b/content/test/gpu/gpu_tests/pixel_test_pages.py
@@ -291,6 +291,12 @@ def MacSpecificPages(base_name):
       test_rect=[0, 0, 300, 300],
       revision=1,
       browser_args=non_chromium_image_args),
+    PixelTestPage(
+      'pixel_webgl_noalpha_implicit_clear.html',
+      base_name + '_WebGLGreenTriangle_NonChromiumImage_ImplicitClear',
+      test_rect=[0, 0, 300, 300],
+      revision=1,
+      browser_args=non_chromium_image_args),

[Ken Russell (switch to Gerrit), 2016/12/01 07:20:43]

Please add the new page to the set of DefaultPages, above, instead of the
MacSpecificPages. (Running with non_chromium_image_args defeats the purpose of
this test, btw.) There's a chance this test might catch a regression on another
platform before it happens. I suggest a name like
WebGLTransparentGreenTriangle_NoAlpha_ImplicitClear.

[Kai Ninomiya, 2016/12/01 23:30:19]

Done.

 
     # On macOS, test CSS filter effects with and without the CA compositor.
     PixelTestPage(