Make ui::Snapshot asynchronous on Android, remove CompositeAndReadback.

content/test/gpu/page_sets/pixel_tests.py

Index: content/test/gpu/page_sets/pixel_tests.py
diff --git a/content/test/gpu/page_sets/pixel_tests.py b/content/test/gpu/page_sets/pixel_tests.py
index 897893aece7724d3ce92cb46309b33786af90fab..254e047e484ca3107d10d4d85c0f84d14ef649bb 100644
--- a/content/test/gpu/page_sets/pixel_tests.py
+++ b/content/test/gpu/page_sets/pixel_tests.py
@@ -34,20 +34,20 @@ class PixelTestsPageSet(page_set_module.PageSet):
     self.AddPage(PixelTestsPage(
       url='file://../../data/gpu/pixel_canvas2d.html',
       name='Pixel.Canvas2DRedBox',
-      test_rect=[0, 0, 400, 300],
-      revision=2,
+      test_rect=[0, 0, 300, 300],
+      revision=3,
       page_set=self))
 
     self.AddPage(PixelTestsPage(
       url='file://../../data/gpu/pixel_css3d.html',
       name='Pixel.CSS3DBlueBox',
-      test_rect=[0, 0, 400, 300],
-      revision=5,
+      test_rect=[0, 0, 300, 300],
+      revision=6,
       page_set=self))
 
     self.AddPage(PixelTestsPage(
       url='file://../../data/gpu/pixel_webgl.html',
       name='Pixel.WebGLGreenTriangle',
-      test_rect=[0, 0, 400, 300],
-      revision=6,
+      test_rect=[0, 0, 300, 300],
+      revision=7,

[Ken Russell (switch to Gerrit), 2014/05/13 23:14:45]

The GPU try servers aren't allowed to generate new reference images, so all of
the GPU try jobs (including the linux_gpu_triggered_tests job which is now part
of the CQ) will fail. Along with the increment of these version numbers, please
modify src/content/test/gpu/gpu_tests/pixel_expectations.py in this CL and mark
all of the tests as failing, pointing to this bug. Once this CL lands, then
please submit another one which removes the failure expectations. Thanks.

[danakj, 2014/05/13 23:18:07]

ok done, can you please verify i did it correctly?

       page_set=self))