[cc] Change semantics of fixed-pos container layer

cc/layers/layer_position_constraint_unittest.cc

Index: cc/layers/layer_position_constraint_unittest.cc
diff --git a/cc/layers/layer_position_constraint_unittest.cc b/cc/layers/layer_position_constraint_unittest.cc
index 1afc4554cf0c29fca8eaa4bfa3178743e580d3cb..32fa24fb737633662c31c930c54a8ff04c859987 100644
--- a/cc/layers/layer_position_constraint_unittest.cc
+++ b/cc/layers/layer_position_constraint_unittest.cc
@@ -118,10 +118,11 @@ class LayerPositionConstraintTest : public testing::Test {
     root_->SetBounds(clip_bounds);
 
     inner_viewport_container_layer_->SetMasksToBounds(true);
+    inner_viewport_container_layer_->SetIsContainerForFixedPositionLayers(true);
     scroll_layer_->SetScrollClipLayerId(inner_viewport_container_layer_->id());
-    scroll_layer_->SetIsContainerForFixedPositionLayers(true);
 
     outer_viewport_container_layer_->SetMasksToBounds(true);
+    outer_viewport_container_layer_->SetIsContainerForFixedPositionLayers(true);
     child_->SetScrollClipLayerId(outer_viewport_container_layer_->id());
     grand_child_->SetScrollClipLayerId(outer_viewport_container_layer_->id());
 
@@ -211,7 +212,6 @@ TEST_F(LayerPositionConstraintTest,
      ScrollCompensationForFixedPositionLayerWithDirectContainer) {
   // This test checks for correct scroll compensation when the fixed-position
   // container is the direct parent of the fixed-position layer.
-  child_->SetIsContainerForFixedPositionLayers(true);
   grand_child_->SetPositionConstraint(fixed_to_top_left_);
 
   CommitAndUpdateImplPointers();
@@ -278,7 +278,6 @@ TEST_F(LayerPositionConstraintTest,
      ScrollCompensationForFixedPositionLayerWithDistantContainer) {
   // This test checks for correct scroll compensation when the fixed-position
   // container is NOT the direct parent of the fixed-position layer.
-  child_->SetIsContainerForFixedPositionLayers(true);
   grand_child_->SetPosition(gfx::PointF(8.f, 6.f));
   great_grand_child_->SetPositionConstraint(fixed_to_top_left_);
 
@@ -430,7 +429,6 @@ TEST_F(LayerPositionConstraintTest,
   // container contributes to a different render surface than the fixed-position
   // layer. In this case, the surface draw transforms also have to be accounted
   // for when checking the scroll delta.
-  child_->SetIsContainerForFixedPositionLayers(true);
   grand_child_->SetPosition(gfx::PointF(8.f, 6.f));
   grand_child_->SetForceRenderSurfaceForTesting(true);
   great_grand_child_->SetPositionConstraint(fixed_to_top_left_);
@@ -556,7 +554,6 @@ TEST_F(LayerPositionConstraintTest,
   great_grand_child_->AddChild(fixed_position_child);
 
   // Actually set up the scenario here.
-  child_->SetIsContainerForFixedPositionLayers(true);
   grand_child_->SetPosition(gfx::PointF(8.f, 6.f));
   grand_child_->SetForceRenderSurfaceForTesting(true);
   great_grand_child_->SetPosition(gfx::PointF(40.f, 60.f));
@@ -831,7 +828,6 @@ TEST_F(LayerPositionConstraintTest,
   // should be treated like a layer that contributes to a render target, and
   // that render target is completely irrelevant; it should not affect the
   // scroll compensation.
-  child_->SetIsContainerForFixedPositionLayers(true);
   child_->SetForceRenderSurfaceForTesting(true);
   grand_child_->SetPositionConstraint(fixed_to_top_left_);
 
@@ -913,11 +909,7 @@ TEST_F(LayerPositionConstraintTest,
   // This test checks the scenario where a fixed-position layer also happens to
   // be a container itself for a descendant fixed position layer. In particular,
   // the layer should not accidentally be fixed to itself.
-  child_->SetIsContainerForFixedPositionLayers(true);
   grand_child_->SetPositionConstraint(fixed_to_top_left_);
-
-  // This should not confuse the grand_child. If correct, the grand_child would
-  // still be considered fixed to its container (i.e. "child").
   grand_child_->SetIsContainerForFixedPositionLayers(true);
 
   CommitAndUpdateImplPointers();
@@ -985,7 +977,6 @@ TEST_F(LayerPositionConstraintTest,
   // In this situation, the parent fixed-position layer will receive
   // the scroll compensation, and the child fixed-position layer does not
   // need to compensate further.
-  child_->SetIsContainerForFixedPositionLayers(true);
   grand_child_->SetPositionConstraint(fixed_to_top_left_);
 
   // Note carefully - great_grand_child is fixed to bottom right, to test
@@ -1049,9 +1040,8 @@ TEST_F(LayerPositionConstraintTest,
       make_scoped_refptr(new LayerWithForcedDrawsContent());
   great_grand_child_->AddChild(great_great_grand_child);
 
-  child_->SetIsContainerForFixedPositionLayers(true);
   grand_child_->SetPositionConstraint(fixed_to_top_left_);
-  great_grand_child_->SetIsContainerForFixedPositionLayers(true);
+  grand_child_->SetIsContainerForFixedPositionLayers(true);
   great_grand_child_->SetScrollClipLayerId(root_->id());
   great_great_grand_child->SetPositionConstraint(fixed_to_top_left_);