Use the solid color detection to create solid layers

cc/trees/layer_tree_host_pixeltest_readback.cc

Index: cc/trees/layer_tree_host_pixeltest_readback.cc
diff --git a/cc/trees/layer_tree_host_pixeltest_readback.cc b/cc/trees/layer_tree_host_pixeltest_readback.cc
index 12008f0d7dad50a43a97a9288247918a31cae16b..c519f933d420a2917a3965fad5acfeec3dcd391f 100644
--- a/cc/trees/layer_tree_host_pixeltest_readback.cc
+++ b/cc/trees/layer_tree_host_pixeltest_readback.cc
@@ -932,21 +932,15 @@ class LayerTreeHostReadbackDeviceScalePixelTest
 
   virtual void DrawLayersOnThread(LayerTreeHostImpl* host_impl) OVERRIDE {
     LayerImpl* root_impl = host_impl->active_tree()->root_layer();

[danakj, 2014/09/15 16:26:35]

Just remove all these layers, they're unused.

[hendrikw, 2014/09/15 16:59:40]

Acknowledged.

+    EXPECT_EQ(device_scale_factor_,
+              host_impl->active_tree()->device_scale_factor());
 
     FakePictureLayerImpl* background_impl =
         static_cast<FakePictureLayerImpl*>(root_impl->children()[0]);
-    EXPECT_EQ(device_scale_factor_,
-              background_impl->HighResTiling()->contents_scale());

[vmpstr, 2014/09/15 15:45:08]

Why this change?

[danakj, 2014/09/15 16:26:35]

This test makes solid color quads now so it has no tilings. It's still testing a
readback with a DSF so I think that's fine.

[hendrikw, 2014/09/15 16:59:40]

Because we no longer have HiResTiling(), i.e. it is nullptr, the layer is solid.

-
     FakePictureLayerImpl* green_impl =
         static_cast<FakePictureLayerImpl*>(background_impl->children()[0]);
-    EXPECT_EQ(device_scale_factor_,
-              green_impl->HighResTiling()->contents_scale());
-
     FakePictureLayerImpl* blue_impl =
         static_cast<FakePictureLayerImpl*>(green_impl->children()[0]);
-    EXPECT_EQ(device_scale_factor_,
-              blue_impl->HighResTiling()->contents_scale());
   }
 
   float device_scale_factor_;