Reland "Shouldn't access LayerTreeTest::layer_tree_host on impl thread"

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 1b10e416421115196994167c37e81b5e48f0e612..8bfaa1524f90efb9dbc7ccaea791534e2b14e933 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -2150,6 +2150,10 @@ class LayerTreeHostTestShutdownWithOnlySomeResourcesEvicted
         child_layer2_(FakeContentLayer::Create(&client_)),
         num_commits_(0) {}
 
+  virtual void InitializeSettings(LayerTreeSettings* settings) OVERRIDE {
+    settings->impl_side_painting = false;
+  }
+
   virtual void BeginTest() OVERRIDE {
     layer_tree_host()->SetViewportSize(gfx::Size(100, 100));
     root_layer_->SetBounds(gfx::Size(100, 100));