cc: Fix non root copy request visible rect in HighDPI

cc/test/layer_tree_host_common_test.cc

Index: cc/test/layer_tree_host_common_test.cc
diff --git a/cc/test/layer_tree_host_common_test.cc b/cc/test/layer_tree_host_common_test.cc
index 6d40f6cf2b9e983ef9e89ebcf29ac0972e34d675..aabd43cf2ae2abb1aa4519820ae67d8e00833310 100644
--- a/cc/test/layer_tree_host_common_test.cc
+++ b/cc/test/layer_tree_host_common_test.cc
@@ -173,6 +173,10 @@ void LayerTreeHostCommonTestBase::ExecuteCalculateDrawProperties(
     float device_scale_factor,
     float page_scale_factor,
     LayerImpl* page_scale_layer) {
+  if (device_scale_factor !=
+      root_layer->layer_tree_impl()->device_scale_factor())
+    root_layer->layer_tree_impl()->property_trees()->needs_rebuild = true;
+
   root_layer->layer_tree_impl()->SetDeviceScaleFactor(device_scale_factor);
 
   EXPECT_TRUE(page_scale_layer || (page_scale_factor == 1.f));